Dose is the sum of the individual doses received in a given period by a specific population from exposure to a specified source of radiation.

The collective effective dose is the sum of the individual doses received in a given period by a specific population from exposure to a specific source of radiation. It is the dose Quantity S, calculated as the sum of all individual effective doses over the time period or during the operation being considered due to ionizing radiation. It may be used to estimate the total health effects of a process or accidental release involving ionizing radiation to an exposed population.

Ithink the answer is d.