Where are most likely to be affected by caner-inducing agents according to the passage （）

A．When a chromosome breaks apart near an oncogene and its control functions fail.
B．When people drink too much and are easy to get tired.
C．When people smoke too much and are difficult to get to sleep.
D．When people eat too much petroleum-based products.

A. genes that can kill cancer
B. genes that will lead to leukemia
C. viruses that can kill AIDS
D. genes that will lead to cancer