**Core Concept**
The question is testing knowledge of **renal ectopia**, a congenital anomaly where the kidney is located outside its normal position. This condition can result from abnormal migration of the kidney during fetal development. Understanding the incidence of such anomalies is crucial for diagnosis and management.

**Why the Correct Answer is Right**
The correct answer choice is not provided, but typically, **renal ectopia** occurs in approximately 1 in 900 to 1 in 3000 births, with some variations based on the population studied. The mechanism involves the kidney failing to ascend to its normal lumbar position during embryogenesis, often due to genetic or environmental factors affecting **ureteric bud** formation or **metanephric** tissue development.

**Why Each Wrong Option is Incorrect**
**Option A:** Without the specific percentage or ratio, it's hard to comment, but typically, ectopia is not as common as other congenital anomalies.
**Option B:** Similarly, without specifics, it's challenging to address directly, but the incidence of renal ectopia is usually reported in a range rather than a single figure.
**Option C:** Again, lacking the exact figure, but generally, the incidence is well-documented in medical literature and not as high as some other congenital issues.
**Option D:** This option is also unclear without specifics, but the key is understanding that renal ectopia incidence is relatively rare compared to other renal issues.

**Clinical Pearl / High-Yield Fact**
A crucial point to remember is that **renal ectopia** can be associated with other congenital anomalies, including **ureteral duplication** and **vesicoureteral reflux**. Recognizing these potential associations is vital for comprehensive patient evaluation and care.

**Correct Answer:** Not provided in the query.