Shontae has been taking her resting heart rate each morning as soon as she wakes up. over a four month period her resting heart rate has gone from 87 beats per minute to 76 beats per minute. during this same time period shontae has been actively participating in a cardiovascular fitness program 5 days per week. which statement most accurately reflects the change in her resting heart rate level? a) a four month period is not enough time to affect change on the cardiovascular system. b) a decrease in resting heart rate means her cardiovascular system is working less efficiently. c) a decrease in resting heart rate means her cardiovascular system is working more efficiently. d) her cardiovascular system is showing no effect from the exercise program.