Studies Conducted on First Generation Cell Phone Users Showed That

Studies conducted on first generation cell phone users showed that

A) Tumors usually grew on the side of the head of which there was frequent contact with a cell phone.
B) Those who used cell phones frequently did not have a higher rate of brain tumors than those who infrequently used cell phones.
C) Tumors were more likely to develop in males.
D) There was no evidence of increased risk of brain tumors for frequent cell phone users.