Answer: (A) or “Increased physical activity and cardiovascular endurance will lower your Resting Heart Rate
This is because as you continue to train your heart, it becomes more effective in delivering blood. Your RHR will drop due to the bigger bursts of blood your heart is pumping out in which case fewer beats or pumps are needed.
This takes some work load off of the heart and is one of the main reasons why this method of exercise is recommended by Heath professionals.