A Patient Who Has Stable Angina Pectoris and a History

A patient who has stable angina pectoris and a history of previous myocardial infarction takes nitroglycerin and verapamil.The patient asks the primary care nurse practitioner (NP) why it is necessary to take verapamil.The NP should tell the patient that verapamil:

A) improves blood flow and oxygen delivery to the heart.
B) increases the rate of contraction of the cardiac muscle.
C) increases the force of contraction of the cardiac muscle.
D) has a positive inotropic effect to increase cardiac output.