Question

a. gastrocnemius
b. soleus
c. tibialis anterior
d. hamstrings

Explanation:

The gastrocnemius is the prominent muscle on the back - of the lower leg as shown in the image. It is a major muscle in the calf. The soleus is deeper and flatter, the tibialis anterior is on the front of the lower leg, and the hamstrings are on the back of the thigh.

Answer:

A. Gastrocnemius