**Core Concept**
The question tests the understanding of the collateral venous drainage pathway of the testes, specifically after interruption of the testicular vein. The cremasteric vein plays a crucial role in this collateral circulation.

**Why the Correct Answer is Right**
When the testicular vein is divided for the treatment of varicocele, the cremasteric vein assumes the primary role in draining venous blood from the testes. This is because the cremasteric vein is part of a rich collateral network that includes the pampiniform plexus, the deferential vein, and the internal spermatic vein. The cremasteric vein drains into the inferior epigastric vein, which ultimately empties into the external iliac vein. This collateral pathway ensures that venous blood from the testes continues to be drained, despite the interruption of the testicular vein.

**Why Each Wrong Option is Incorrect**
**Option B:** The dorsal vein of the penis is not directly involved in the drainage of venous blood from the testes. It primarily drains the penile skin and glans, and is not part of the collateral venous pathway of the testes.

**Option C:** The internal pudendal vein is responsible for draining the external genitalia, including the penis and scrotum, but it is not involved in the drainage of the testes.

**Option D:** The pampiniform plexus is a network of veins that surrounds the testicular artery and plays a role in the drainage of the testes, but it is not the primary pathway for drainage after division of the testicular vein.

**Clinical Pearl / High-Yield Fact**
The cremasteric vein is an important landmark in urological surgery, and its preservation is crucial to maintain collateral venous drainage of the testes.

**✓ Correct Answer: A. Cremasteric vein**