What is the relationship between Rad and Gray?

The correct choice is based on the established relationship between the units of radiation dose measurement: the rad and the gray.

Specifically, 1 rad is defined as 0.01 gray. This relationship arises from the fact that the gray is a more modern SI (International System of Units) unit for measuring absorbed radiation dose, while the rad is an older unit that has since been largely phased out in favor of the gray. The conversion factor reflects this relationship; thus, 100 rads are equal to 1 gray.

Understanding this conversion is vital for accurate communication in the field of radiology and radiation therapy, as it ensures that professionals are using standardized measures when discussing radiation exposure and its effects. This also explains why other options are not valid, as they do not reflect the correct conversion factor between these two units.