Question

the muscle in the abdominal region whose fibers run on a diagonal: triceps brachii rectus femoris obliques transversus abdominus

Explanation:

The rectus femoris is a muscle in the thigh. The triceps brachii is in the arm. The transverse abdominis has fibers running transversely. The obliques (external and internal) in the abdominal region have fibers running diagonally.

Answer:

obliques