**Core Concept**
The flexor digitorum profundus (FDP) muscle is one of the intrinsic muscles of the hand, responsible for flexion of the fingers at the interphalangeal joints. Its motor innervation is derived from the anterior interosseous branch of the median nerve and the ulnar nerve.

**Why the Correct Answer is Right**
The FDP muscle has a unique dual nerve supply, which is essential for its function. The anterior interosseous branch of the median nerve supplies the lateral half of the muscle, while the ulnar nerve supplies the medial half. This dual innervation allows for precise control over finger movement. The median nerve's contribution is through the anterior interosseous branch, which arises from the median nerve after it passes through the carpal tunnel. The ulnar nerve, on the other hand, provides the motor supply to the medial half of the FDP muscle.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not specify the dual nerve supply of the FDP muscle.
**Option B:** This option is incorrect as the radial nerve does not contribute to the motor innervation of the FDP muscle.
**Option C:** This option is incorrect as the musculocutaneous nerve does not supply the FDP muscle.

**Clinical Pearl / High-Yield Fact**
It is essential to remember the dual nerve supply of the FDP muscle to avoid confusion during surgical procedures or when assessing motor function in patients with nerve injuries.

**Correct Answer: C. The FDP muscle is supplied by the anterior interosseous branch of the median nerve and the ulnar nerve.**