**Core Concept**
Non-scarring loss of hair refers to a condition where there is hair loss without any visible scarring on the scalp. This is often due to **alopecia**, which can be caused by various factors such as hormonal imbalances, autoimmune diseases, or genetic predisposition.

**Why the Correct Answer is Right**
The correct answer is related to the most common cause of non-scarring hair loss, which is **androgenetic alopecia**, also known as male or female pattern baldness. This condition is caused by the conversion of **testosterone** to **dihydrotestosterone (DHT)**, which leads to hair follicle shrinkage and eventually hair loss.

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because it is not a common cause of non-scarring hair loss.
**Option B:** Incorrect as it is related to scarring hair loss.
**Option C:** Incorrect because it is not directly related to hair loss.

**Clinical Pearl / High-Yield Fact**
Non-scarring hair loss can be treated with **minoxidil** or **finasteride**, which can help slow down hair loss and promote hair growth.

**Correct Answer:** D. Alopecia areata