Men's Testicles Are Located in the Scrotum Instead of in the Abdomen

Men's testicles are located in the scrotum instead of in the abdomen because:

A) testosterone from the testicles would damage other internal organs.
B) for sperm to fertilize the egg,there is a precise distance that they must travel.
C) to produce sperm,they need to be a few degrees lower than body temperature.
D) they are safer there.
E) they cannot make testosterone anywhere else.