**Core Concept**
The helicine arteries are a branch of the arteries supplying the penis, playing a crucial role in erection. They are part of the deep arterial plexus of the penis, which is responsible for the increase in blood flow during an erection. The helicine arteries are characterized by their spiral or coiled shape, which allows for the regulation of blood flow.

**Why the Correct Answer is Right**
The helicine arteries are a branch of the internal iliac artery, specifically the internal pudendal artery. The internal pudendal artery then divides into the dorsal artery of the penis and the cavernosal arteries, which further branch into the helicine arteries. The helicine arteries are responsible for the regulation of blood flow into the corpora cavernosa, which become engorged with blood during an erection. The helicine arteries are richly innervated with sympathetic and parasympathetic nerve fibers, which play a crucial role in the regulation of erection.

**Why Each Wrong Option is Incorrect**
**Option A:** The internal carotid artery is a major artery supplying the head and neck, and is not related to the blood supply of the penis.
**Option B:** The external iliac artery is a branch of the common iliac artery, and it supplies the lower limb, not the penis.
**Option C:** The common iliac artery is a major artery that divides into the internal and external iliac arteries, but it does not directly supply the penis.

**Clinical Pearl / High-Yield Fact**
The helicine arteries are a critical component of the penile blood supply, and their dysfunction can lead to erectile dysfunction.

**Correct Answer:** D. The internal pudendal artery.