-Kevin Owns a Personal Training Gym in Darwin

-Kevin owns a personal training gym in Darwin. He charges $41 per session. The above table shows the marginal product of trainers in Kevin's gym. If Kevin hires four trainers, the value of marginal product of the fourth trainer equals

A) 1 client.
B) $10.25.
C) $41.
D) $410.
E) 10 clients.