Which variable returns code from operations that return true or false?

This question is asking about a special variable in MySQL that tells you if a command was successful or not. Think of it like a light switch:
* On means the command worked. * Off means something went wrong.
The variable that holds this information is called $rc.
So the answer is Option A: $rc
Let's break down why the other options are incorrect:
* $rv: This variable is not used in MySQL.
* $rows: This variable stores the number of rows affected by a query.
* $ary: This variable isn't a standard MySQL variable.