**Core Concept**
The kidneys receive approximately 20-25% of the cardiac output, which is relatively high compared to other organs, making them highly susceptible to ischemic injury due to their high metabolic rate and oxygen demand.

**Why the Correct Answer is Right**
Ischemic kidney injury occurs when there is a reduction in blood flow to the kidneys, leading to a decrease in oxygen delivery and subsequent cellular damage. The kidneys' high oxygen demand is due to their role in filtering waste products from the blood and regulating electrolyte balance. The renal medulla, in particular, is a hypoxic region due to the countercurrent exchange mechanism, which concentrates waste products and ions. However, the kidneys do not receive 30% of the cardiac output, which is a crucial fact to remember when assessing renal function and perfusion.

**Why Each Wrong Option is Incorrect**
**Option A:** Healthy kidneys indeed account for 10% of total oxygen consumption, making them a significant contributor to overall oxygen demand.
**Option B:** The renal medulla is indeed a highly hypoxic region of the body, which is a result of the countercurrent exchange mechanism.
**Option C:** Ischemia associated with rhabdomyolysis is indeed more dangerous, as the breakdown of muscle tissue can lead to a surge in potassium levels and further exacerbate renal injury.

**Clinical Pearl / High-Yield Fact**
The kidneys' high oxygen demand and relative hypoxia make them vulnerable to ischemic injury, which can occur due to various factors such as hypotension, shock, or vascular obstruction. It is essential to remember the kidneys' unique physiology and the consequences of reduced perfusion.

**✓ Correct Answer: D. Healthy kidneys receive 30% of the cardiac output**