**Core Concept**
Congenital adrenal hyperplasia (CAH) is a group of inherited disorders that affect the adrenal glands' ability to produce hormones, specifically cortisol and aldosterone. In CAH, the enzyme 21-hydroxylase is often deficient, leading to an accumulation of 17-hydroxyprogesterone (17-OHP) and an overproduction of androgens.

**Why the Correct Answer is Right**
The 17-OHP level is elevated in CAH due to the impaired conversion of 17-hydroxyprogesterone to 11-deoxycortisol by the 21-hydroxylase enzyme. This enzyme deficiency leads to a shunting of precursors towards the production of androgens, resulting in an increase in 17-OHP levels. In a 1-year-old child with CAH, the 17-OHP level is typically significantly elevated, often above 2000 ng/dL.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is not provided.
* **Option B:** Typically, a 17-OHP level of less than 200 ng/dL is considered normal in a child.
* **Option C:** While a 17-OHP level of 200-2000 ng/dL may be seen in some cases of CAH, it is not specific enough to confirm the diagnosis.
* **Option D:** This option is not provided.

**Clinical Pearl / High-Yield Fact**
In CAH, the 17-OHP level can be used as a diagnostic marker, but it is essential to note that a positive family history and clinical presentation are also crucial for diagnosis. A 17-OHP level above 2000 ng/dL in a child is highly suggestive of CAH, but a normal level does not rule out the condition.

**Correct Answer: B. 200 ng/dL.**