What is blood pressure a measurement of? A. the force applied by the blood to the inner walls of the blood vessels as it circulates through the body B. the force applied by the blood to the outer walls of the blood vessels as it circulates through the body C. the force applied by the inner walls of the blood vessels to the blood as it circulates through the body D. the force applied by the outer walls of the blood vessels to the blood as it circulates through the body