The radiosensitivity of ova:
a. varies considerably throughout the lifetime of the germ cell.
b. is insignificant because the germ cell is not radiosensitive.
c. varies slightly throughout the lifetime of the germ cell.
d. remains constant throughout the lifetime of the germ cell.

Option A, varies considerably throughout the lifetime of the germ cell.

Explanation:

The radio sensitivity of a cell varies through out its life depending on the stage of exposure,  differentiation pattern, cell division type etc,

For instance, an undifferentiated cells (such as stem cells) has higher radioactive sensitivity as compared to differentiated cell. Like wise cell that divide irregularly are more susceptible to radioactivity as compared to cells that divide regularly. Also the cells that no not divide but have the potential to divide are highly sensitive to radioactivity

As we can see that their are several variables on which the radio sensitivity depends hence this is a process that varies considerably throughout the lifetime of the germ cell.

Option A is correct

the most logical answer would be a