Why Do Radiation Workers Wear a Film Badge

Why do radiation workers wear a film badge?

A) to measure their cumulative level of exposure to radiation
B) to measure the amount of time they spend in close proximity to radiation
C) to monitor the different types of radiation to which they are being exposed
D) to measure the radioactivity in their blood
E) to quickly determine the amount of radiation given off by a piece of radioactive material with which they are working