Final answer:
The ventricles contract during systole and relax during diastole; the answer is a) Systole; Diastole.
Step-by-step explanation:
The contraction of the ventricles is referred to as systole, and the period of ventricular relaxation is called diastole. Therefore, the correct answer to the student's question is: a) Systole; Diastole. During systole, the ventricles contract and pump blood out of the heart, whereas during diastole, the heart muscle is relaxed and blood flows into the heart.