Final answer:
The right testicular vein drains directly into the inferior vena cava (IVC) as part of the venous return from the testes to the heart.
Step-by-step explanation:
The right testicular vein is responsible for draining the testes and is a component of the spermatic cord. It empties directly into the inferior vena cava (IVC), whereas the left testicular vein drains into the left renal vein. This physiological arrangement is essential for the return of deoxygenated blood from the testes back to the heart. Thus, the correct answer to the question - the right testicular vein drains into the A. IVC.