One of the reasons why statins are effective in reducing the risk of cardiovascular disease is
a. they increase the transport of cholesterol away from the liver
b. they reduce the protein content of ldls
c. they decrease the incidence of cholesterol deposition in arterial walls
d. all of the listed responses are correct.

c. they decrease the incidence of cholesterol deposition in arterial walls.  

Explanation:

The statin is a drug which block the action of the liver enzyme which controls the production of the cholesterol. The cholesterol is a biomolecule which aggregate inside the blood vessels such as arteries may lead to arteriosclerosis. This condition will lead to increase in blood pressure which may lead to the condition of hypertension or heart attack.

By lowering the levels of the cholesterol in the arteries the statins can reduce the risk of cardiovascular disease.  

The correct answer will be option D.

Explanation:

Statins are a class of drug provided in the medication to treat cardiovascular disease.

Statins act by reducing the amount of bad cholesterol called low-density lipoprotein (LDL) from blood, preventing the formation of cholesterol from the liver by blocking the enzyme and pathway of cholestrol synthesis and the degradation of the deposited cholestrol form the arterial walls which make the arteries narrow.

Thus, option D is the correct answer.

i think it is true in my reasonment ..