Upon vigorous exercise, your heart rate increases to 200 beats per minute to supply sufficient oxygen to muscles. which is responsible for this regulation of the heart rate? semilunar valves sinoatrial node aorta

The option which is responsible for this regulation of the heart rate is B. the sinoatrial node. It is also known as "the heart's natural pacemaker," meaning that is regulates blood pressure in your body, and thus your heart rate as well. It is the part of your body that makes the heart contract and thus pump blood and it regulates how much of that blood is going to be pumped.