The DNS record types that hold an IP address are the A and AAAA records. These records are used to map a domain name to an IP address of the host, which is necessary for establishing a connection between a client and a server. The A record holds a 32-bit IPv4 address, while the AAAA record holds a 128-bit IPv6 address. For example, the A record for www.example.com could be:
www.example.com. IN A 192.0.2.1
This means that the domain name www.example.com resolves to the IPv4 address 192.0.2.1. Similarly, the AAAA record for www.example.com could be:
www.example.com. IN AAAA 2001:db8::1
This means that the domain name www.example.com resolves to the IPv6 address 2001:db8::1.
The other options are incorrect because:
NS records are used to specify the authoritative name servers for a domain. They do not hold an IP address, but a domain name of the name server. For example, the NS record for example.com could be:
example.com. IN NS ns1.example.com.
This means that the name server ns1.example.com is authoritative for the domain example.com.
MX records are used to specify the mail exchange servers for a domain. They do not hold an IP address, but a domain name of the mail server and a preference value. For example, the MX record for example.com could be:
example.com. IN MX 10 mail.example.com.
This means that the mail server mail.example.com has a preference value of 10 for receiving email for the domain example.com.
CNAME records are used to create an alias for a domain name. They do not hold an IP address, but another domain name that the alias points to. For example, the CNAME record for www.example.com could be:
www.example.com. IN CNAME example.com.
This means that the domain name www.example.com is an alias for the domain name example.com.
Reference:
DNS Record Types: Defined and Explained - Site24x7
List of DNS record types - Wikipedia

Explanation
The backslash character () is used to escape the meaning of the next character in a command line. This means that the next character is treated as a literal character, not as a special character. For example, if you want to use a space in a file name, you can use a backslash before the space to prevent the shell from interpreting it as a separator. Similarly, if you want to split a long command line across multiple lines, you can use a backslash at the end of each line to tell the shell that the command is not finished yet. The shell will ignore the newline character and continue reading the next line as part of the same command.
For example, you can write:
ls -l/home/user/Documents
instead of:
ls -l /home/user/Documents
Both commands will produce the same output, but the first one is easier to read and type. References:
* Linux Essentials - Linux Professional Institute (LPI), section 2.1.2
* 2.1 Command Line Basics - Linux Professional Institute Certification Programs, slide 7.

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