**Core Concept**
The lymphatic drainage of the glans penis is an essential aspect of understanding the anatomy of the penis and its associated lymphatic system. The lymph from the glans penis follows a specific pathway to return to the bloodstream, and knowledge of this pathway is crucial for surgeons and clinicians to avoid lymphedema and other complications.

**Why the Correct Answer is Right**
The lymph from the glans penis primarily drains into the deep inguinal lymph nodes. This is because the glans penis receives its lymphatic supply from the superficial and deep dorsal veins, which ultimately drain into the deep inguinal lymph nodes. The deep inguinal lymph nodes are located in the femoral canal, near the femoral vein, and serve as the primary lymphatic drainage site for the genitalia and lower limbs. The lymph from the deep inguinal lymph nodes then proceeds to the iliac lymph nodes and eventually to the cisterna chyli, where it enters the thoracic duct and returns to the bloodstream.

**Why Each Wrong Option is Incorrect**
**Option A:** External iliac lymph nodes are not the primary site of lymphatic drainage for the glans penis, although they do receive lymph from the deep inguinal lymph nodes.

**Option B:** Internal iliac lymph nodes receive lymph from the pelvic organs, but they are not the primary site of lymphatic drainage for the glans penis.

**Option D:** Superficial inguinal lymph nodes are involved in the lymphatic drainage of the skin of the penis, but they are not the primary site of lymphatic drainage for the glans penis.

**Clinical Pearl / High-Yield Fact**
It's essential to note that the lymphatic drainage of the penis can be affected by surgery, trauma, or disease, leading to lymphedema and other complications. Surgeons and clinicians must carefully consider the lymphatic pathways when performing procedures on the genitalia to avoid these complications.

**✓ Correct Answer: C. Deep inguinal lymph nodes**