Okay, let's tackle this question. The question is about the innervation of the interossei muscles. First, I need to recall which nerves supply these muscles. The interossei are in the hand, right? There are two types: the dorsal and palmar interossei.

The palmar interossei are the ones that adduct the fingers, and the dorsal interossei abduct them. Now, the innervation. I remember that the hand's intrinsic muscles are mainly supplied by the ulnar nerve. Specifically, the deep branch of the ulnar nerve. The median nerve also innervates some muscles in the hand, like the thenar muscles, but not the interossei. The radial nerve is more for the extensors, so probably not involved here. So the answer should be the deep branch of the ulnar nerve. Let me check the options again. The user didn't list the options, but based on standard questions, the options might be different branches of the ulnar nerve or other nerves. The correct answer is the deep branch of the ulnar nerve. The superficial branch might be a distractor. Also, the anterior interosseous nerve is a branch of the median nerve, so that's not it. The radial nerve's posterior interosseous branch is another possible distractor. So the correct answer is the deep branch of the ulnar nerve.

**Core Concept**
The interossei muscles (dorsal and palmar) are intrinsic hand muscles innervated by the **deep branch of the ulnar nerve** (C8-T1). This nerve arises from the medial cord of the brachial plexus and is critical for fine motor control of the hand.

**Why the Correct Answer is Right**
The **deep branch of the ulnar nerve** directly innervates all interossei muscles. The dorsal interossei abduct fingers, while the palmar interossei adduct them. This nerve also supplies the hypothenar muscles, adductor pollicis, and medial half of the flexor digitorum profundus. Its terminal branch, the deep ulnar nerve, runs along the medial aspect of the metacarpal bones to reach these muscles.

**Why Each Wrong Option is Incorrect**
**Option A:** *Superficial branch of the ulnar nerve*—Supplies only the skin over the medial 1.5 fingers and palmar hypothenar region, not muscles.
**Option B:** *Anterior interosseous nerve*—A branch of the median nerve, it innervates the flexor pollicis longus and lateral half of flexor digitorum profundus, not interossei.
**Option C:** *Posterior interosseous nerve*—A branch of the radial nerve, it innervates extensor muscles of the forearm, not hand intrinsic muscles.

**Clinical Pearl**
The **ulnar nerve injury** (e.g., at the elbow) causes "claw hand" due to paralysis of interossei and intrinsic hand muscles. Remember: **"Ulnar = Unhappy, Clawed Hand."** Always test interossei function in suspected ulnar neuropathy.

**Correct Answer: D. Deep branch of the ulnar nerve**

✓ Correct Answer: D. Deep palmar arch