You need to know where all the configuration files for the installed package named “postfix” are located.
Assuming it was installed with rpm, which command will list this information for you?

A.
rpm -qc postfix

B.
rpm -Vc postfix

C.
rpm –config postfix

D.
rpm -listconfig postfix

E.
rpm -qa –config postfix

Explanation/Reference:
-qa –config is invalid
-listconfig is invalid
–config is invalid
-Vc verifies the installation of <package>