**Core Concept**
The anatomical and physiological differences between the right and left kidneys are crucial for surgical procedures, including transplantation. The right kidney is often preferred for transplantation due to its anatomical characteristics, which make it more accessible and easier to implant.

**Why the Correct Answer is Right**
The correct answer is **A**, as the right kidney is indeed not preferred over the left for transplantation. The left kidney is typically the preferred choice for transplantation because it is more easily accessed through a midline incision, and its longer renal vein allows for a smoother surgical procedure. Additionally, the left kidney has a more straightforward vascular anatomy, making it easier to connect to the recipient's blood vessels.

**Why Each Wrong Option is Incorrect**
**Option B:** The right kidney is actually positioned slightly higher than the left due to the presence of the liver and the inferior vena cava, which pushes the right kidney upwards.
**Option C:** The right renal vein is indeed shorter than the left, but this is not a significant concern in transplantation. However, the longer left renal vein is still a more desirable characteristic for surgical procedures.
**Option D:** The right kidney is related to the second part of the duodenum, but this is not a relevant factor in transplantation.

**Clinical Pearl / High-Yield Fact**
When preparing for kidney transplantation, surgeons consider the anatomical differences between the right and left kidneys. The left kidney's longer renal vein and more straightforward vascular anatomy make it the preferred choice for transplantation.

**✓ Correct Answer: A. Rt. kidney is preferred over the left for transplantation**