**Core Concept**
The question describes a scenario of shoulder dystocia during delivery, a condition where the baby's shoulder gets stuck behind the mother's pubic bone after the head has delivered. This can lead to complications such as brachial plexus injury, which affects the nerves controlling the arm.

**Why the Correct Answer is Right**
During a shoulder dystocia, the McRoberts maneuver is often performed to widen the pelvis and facilitate delivery. However, if the baby's arm is caught and stretched, it can cause a brachial plexus injury, specifically a **Erb's palsy**. This injury affects the C5-C6 nerve roots, leading to weakness or paralysis of the arm, characterized by the "waiter's tip" deformity, where the forearm is extended and internally rotated, and the arm hangs limply by the side.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because a brachial plexus injury is a more common complication of shoulder dystocia than a clavicle fracture.
**Option B:** This option is incorrect because a clavicle fracture would not typically cause a limb to hang limply by the side with the forearm extended and internally rotated.
**Option C:** This option is incorrect because while a brachial plexus injury can cause weakness or paralysis of the arm, a radial nerve injury would more likely cause wrist drop rather than the described deformity.

**Clinical Pearl / High-Yield Fact**
In cases of shoulder dystocia, the "rules of 5" are often remembered to minimize complications: 1) the baby's head should be delivered within 5 minutes, 2) the shoulders should be delivered within 5 minutes of the head, and 3) the baby's body should be delivered within 5 minutes of the shoulders. Additionally, the baby's arm should be gently guided down to prevent brachial plexus injury.

**Correct Answer: D. Brachial Plexus Injury.**