The sort command is used to sort the lines of a text file or the output of another command in alphabetical, numerical, or other order. The sort command has the following syntax: sort [options] [file...]. The file argument is the name of one or more files to be sorted. If no file is given, the sort command reads from the standard input, which is usually the keyboard or the output of another command.
The | (pipe) symbol is used to connect the output of one command to the input of another command. This allows the creation of pipelines of commands that process data sequentially. The pipe symbol has the following syntax: command1 | command2. The command1 argument is the name of the first command, whose output is sent to the input of the second command. The command2 argument is the name of the second command, which receives the output of the first command as its input.
Therefore, the command export-logs | sort sorts the output of the export-logs command in alphabetical order. The export-logs command is assumed to be a custom command that exports some logs to the standard output. The sort command receives the output of the export-logs command as its input and sorts it according to the default criteria, which is the first character of each line. The sorted output is then displayed on the screen or can be redirected to a file or another command.
The other options in the question are incorrect because they use the wrong symbols to connect the commands. The < (input redirection) symbol is used to read the input of a command from a file instead of the keyboard. The > (output redirection) symbol is used to write the output of a command to a file instead of the screen. The & (background) symbol is used to run a command in the background, which means the command does not wait for user input and allows the user to run other commands simultaneously. The <> (bidirectional redirection) symbol is used to read and write the input and output of a command from and to the same file. None of these symbols can be used to sort the output of the export-logs command. Reference:
Linux Essentials Version 1.6 Objectives: 3.2. Searching and Extracting Data from Files1 Linux Essentials Version 1.6 Exam Study Resources: Linux Essentials Manual - Chapter 9. The Power of the Command Line - 9.2. Searching and Extracting Data from Files - 9.2.1. The sort Command2 Linux Essentials Version 1.6 Exam Study Resources: Linux Essentials Manual - Chapter 9. The Power of the Command Line - 9.3. Turning Commands into a Script - 9.3.1. Pipes and Redirection2 Linux Essentials Version 1.6 Exam Study Resources: Linux Essentials Manual - Appendix A. Answers to the Exercises - Chapter 9. The Power of the Command Line - 9.2. Searching and Extracting Data from Files - Exercise 9.2.12 Linux Essentials Version 1.6 Exam Study Resources: Linux Essentials Manual - Appendix A. Answers to the Exercises - Chapter 9. The Power of the Command Line - 9.3. Turning Commands into a Script - Exercise 9.3.12

Explanation
The host command is used to resolve a DNS name to an IP address or vice versa. It can also perform other DNS queries, such as finding the mail servers for a domain. The host command has the following syntax: host
[options] [name] [server]. The name argument can be a hostname, such as www.lpi.org, or an IP address, such as 192.168.0.1. The server argument is optional and specifies the name or IP address of the DNS server to query. If no server is given, the default system resolver is used. References:
* Linux Essentials Version 1.6 Objectives: 1.4.1. Demonstrate an understanding of the purpose and types of DNS records1
* Linux Essentials Version 1.6 Exam Study Resources: Linux Essentials Manual - Chapter 10. Network Fundamentals - 10.3. DNS and Hostname Resolution - 10.3.1. The host Command2
* Linux Essentials Version 1.6 Exam Study Resources: Linux Essentials Manual - Appendix A. Answers to the Exercises - Chapter 10. Network Fundamentals - 10.3. DNS and Hostname Resolution - Exercise
10.3.12

The operator that matches the preceding character either zero or one time in a regular expression is the question mark (?). This operator is also known as the optional quantifier, because it makes the preceding character or group of characters optional. For example, the regular expression colou?r matches both color and colour, because the u is optional. The question mark can also be used to modify other quantifiers, such as * (zero or more), + (one or more), or {m,n} (between m and n times), to make them non-greedy, meaning they will match the shortest possible string instead of the longest. For example, the regular expression .*? matches any character zero or more times, but as few as possible. The question mark is one of the basic regular expression operators covered in the Linux Essentials certification program from the Linux Professional Institute (LPI). Reference:
Linux Essentials - Linux Professional Institute (LPI)
Regular Expressions:Difference between 'optional occurrence' and 'zero ...

The top command is a Linux command that shows the running processes on the system. It provides a dynamic real-time view of the system performance and resource usage. The top command can display various information about the processes, such as their process ID, user, priority, state, CPU and memory usage, command name, and more. The top command can also sort the processes by different criteria, such as CPU or RAM consumption, by using the interactive commands. The top command is useful for monitoring the system load and identifying the processes that are consuming the most resources. Reference:
Linux Essentials Topic 104: The Linux Operating System, section 104.3: Basic features and commands of the Linux standard shells.
Linux Essentials Topic 106: Security and File Permissions, section 106.4: Monitor and manage Linux processes.