If a penetration tester was able to access the organization's wireless network from outside of the building using Aircrack-ng, then it means that the wireless network was not secured with strong encryption or authentication methods. Aircrack-ng is a tool that can crack weak wireless encryption schemes such as WEP or WPA-PSK using various techniques such as packet capture, injection, replay, and brute force. To remediate this issue, the client should change to Wi-Fi equipment that supports strong encryption such as WPA2 or WPA3, which are more resistant to cracking attacks. Using directional antennae may reduce the signal range of the wireless network, but it would not prevent an attacker who is within range from cracking the encryption.
Using WEP encryption is not a good recommendation, as WEP is known to be insecure and vulnerable to Aircrack-ng attacks. Disabling Wi-Fi may eliminate the risk of wireless attacks, but it would also eliminate the benefits of wireless connectivity for the organization.

Removing shells: Remove any shell programs installed when performing
the pentest.
Removing tester-created credentials: Be sure to remove any user accounts created during the pentest. This includes backdoor accounts.
Removing tools: Remove any software tools that were installed on the
customer's systems that were used to aid in the exploitation of systems.

Explanation
The key findings indicate that the network device is vulnerable to several attacks, such as sniffing, brute-forcing, or exploiting the SSH daemon. To prevent these attacks, the best recommendations are to create an out-of-band network for management, which means a separate network that is not accessible from the production network, and to implement a better method for authentication, such as SSH keys or certificates.
The other options are not as effective or relevant.

Explanation
The file .scripts/daily_log_backup.sh has permissions set to 777, meaning that anyone can read, write, or execute the file. Since it's owned by the root user and the penetration tester has access to the system with a non-privileged account, this could be a potential avenue for privilege escalation. In a penetration test, after finding such a file, the tester would likely want to explore it and see if it can be leveraged to gain higher privileges. This is often done by inserting malicious code or commands into the script if it's being executed with higher privileges, such as root in this case.