What is the purpose of the mesh/whatcage used in the hammer event​

The hammer throw is one of the four throwing events in regular track and field competitions, along with the discus throw, shot put and javelin. The "hammer" used in this sport is not like any of the tools also called by that name. It consists of a metal ball attached by a steel wire to a grip. The size of the ball varies between men's and women's competitions.

a lot ig i am not sure

c would be the answer