A medical researcher measured the diastolic wall thicknesses of the arteries in a young, healthy test subject. The test subject came back 20 years later to have the measurements repeated. The measurements revealed that the subject's artery walls were half as thick as they were originally. Which of the following is the most likely long-term effect if the measured trend continues?

a) Arteries and veins will fuse, causing oxygenated and deoxygenated blood to mix.

b) Arteries will be unable to withstand the pressure exerted by the heart, causing an aneurysm.

c) Blood volume will increase, causing the kidneys to work harder to maintain blood pressure.

d) Blood pressure will decrease, causing nausea, dizziness, loss of consciousness, and potential death.