Answer:
exposure A quantity used to express external ionizing radiation, or to indicate presence of radionuclides or radiation affecting individuals or populations (for example, “exposure” to radionuclides in the environment). gray (Gy) The SI unit of absorbed dose. 1 Gy equals an absorbed dose of 1 J/kg (100 rad).
Explanation:
I believe it is D. I researched it and it explained the same thing as D