Question

a. triceps brachii
b. deltoid
c. biceps brachii
d. quadriceps

Explanation:

The highlighted muscles in the image are located on the front - side of the upper arm. The biceps brachii is the muscle on the front of the upper arm. The triceps brachii is on the back of the upper arm, the deltoid is on the shoulder, and the quadriceps are on the front of the thigh.

Answer:

C. Biceps brachii