Answer:
C.gamma rays
Step-by-step explanation:
Gamma radiations:
Gamma radiations are high energy radiations having no mass.
These radiations are travel at the speed of light.
Gamma radiations can penetrate into the many materials.
These radiations are also used to treat the cancer.
Lead is used for the protection against gamma radiations because of its high molecular density.
The lead apron are used by the person when treated with gamma radiations.
Lead shields are also used in the wall, windows and doors of the room where gamma radiations are treated, in-order to protect the surroundings.