A lab virtual image is always named pc21.local and in variety of testing situation. The administrator wants to use the IP address pc21.local in a script but is concerned it may change from day to day,

Option A is missing the closing parenthesis in the command substitution - MYIP=$(dig pc21.local +short is syntactically invalid and would cause a shell script parse error.

The +norecurse flag directs the dig query to the DNS server without requesting recursive resolution, and +nocomments strips semicolon-prefixed comment lines from the output, making it easier to parse the IP address in a script. This approach ensures a direct DNS query for pc21.local each time the script runs, guaranteeing the IP variable reflects the most recent address assigned to the frequently rebuilt VM.

+mostatus is not a valid dig option, making this command invalid and unable to execute successfully.

+authority returns the authority section of the DNS response, which contains nameserver records rather than the A record IP address needed for the variable.