Some People Have Been Known to Make Money by Selling

Some people have been known to make money by selling blood plasma frequently,planning to do this as often as twice per week.Why is this frequency possible?

A) Plasma only contains fluid and dissolved substances such as proteins that can be rapidly replaced.
B) Plasma contains platelets which can be replaced quickly.
C) Plasma contains red blood cells which can be replaced quickly.
D) Plasma contains only water and can be rapidly replaced.
E) Plasma is regenerated from the blood cells injected back into the donor.