**Core Concept**
Anti-mullerian hormone (AMH) is a protein hormone produced by the granulosa cells of small antral follicles in the ovaries. It serves as a marker of ovarian reserve, indicating the remaining ovarian follicle count and, by extension, the potential for fertility. A low AMH level is associated with a decreased ovarian reserve.

**Why the Correct Answer is Right**
In low ovarian reserve, the number of small antral follicles is reduced, leading to decreased production of AMH. This decrease in AMH is a direct indicator of the reduced ovarian follicle count and, consequently, the decreased potential for fertility. The ovaries' ability to produce AMH is closely linked to the number of small antral follicles, making AMH a valuable biomarker for assessing ovarian reserve.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is not provided.
**Option B:** This option is not provided.
**Option C:** This option is not provided.

**Clinical Pearl / High-Yield Fact**
A normal AMH level is essential for predicting a good response to ovulation induction therapy. Low AMH levels can help identify patients at risk of poor ovarian response to fertility treatments.

**Correct Answer:** D. Low.