The correct justification for the steps Mary Ann takes to solve the inequality \(-3x \geq 12\) is as follows:
Mary Ann divides both sides of the inequality by \(-3\) to get \(x\). However, when dividing by a negative number, the direction of the inequality sign must be reversed. Therefore, she correctly has:
\[ x \leq -4 \]
So the most accurate response would be:
Mary Ann divides both sides of the inequality by negative 3 and changes the inequality symbol to \(\leq\) to get \(x \leq -4\).
This indicates the correct handling of the negative divisor and the necessary change in the inequality direction.