Which of the following best describes where cholesterol is found in lipoproteins?

a. Inside the lipoprotein sphere as cholesterol ester and on the surface as cholesterol
b. Only in the water rich region outside the surface of the lipoprotein
c. In the water rich region between the surface and inner core of the lipoprotein
d. Only inside the lipoprotein sphere
e. Only on the surfaces of lipoproteins as cholesterol esters