Which of the following professional are more likely to run the risk of a permanent change in their cell's DNA ?

Which of the following professional are more likely to run the risk of

1.	Which of the following professional are more likely to run the risk of a permanent change in their cell's DNA ?
A.	2 alone
B.	1, 2 and 3
C.	1, 2 and 4
D.	1, 3 and 4
Answer» D. 1, 3 and 4