Turbulent flow in humans is a major risk factor for atherosclerosis, the buildup of plaque on arterial endothelium.
Ignoring any potential effects of turbulence, what effect would atherosclerosis have on blood flow?

A) Narrowing of the artery causes the velocity to increase and the hydrostatic pressure to decrease.
B) Narrowing of the artery causes the velocity to increase and the osmotic pressure to decrease.
C) Narrowing of the artery causes the velocity to decrease and the hydrostatic pressure to decrease.
D) Expansion of the artery causes the velocity to decrease and the hydrostatic pressure to increase.

(A) Narrowing of the artery causes the velocity to increase and the hydrostatic pressure to decrease.

Explanation:

Atherosclerosis is a disease which allows plaque to build up inside the arteries of a person. Arteries are responsible to carry oxygen-rich blood to heart and other areas of the body.  

Plaque consists of cholesterol, calcium, fat, and other substances which are present in the blood. Through time, the plaque hardens the arteries and narrows them. That restricts the oxygen-rich blood flow to your organs and to other parts of your body.  

Atherosclerosis can cause serious problems, including stroke and heart attack.

Hence the correct option is  (A).