**Core Concept**
The ovarian cycle is a fundamental aspect of female reproductive physiology, involving the coordinated actions of hormones and ovarian follicles to regulate ovulation and prepare the uterus for potential pregnancy.

**Why the Correct Answer is Right**
The ovarian cycle is primarily regulated by the hypothalamic-pituitary-ovarian axis, where the hypothalamus releases gonadotropin-releasing hormone (GnRH) to stimulate the pituitary gland to release luteinizing hormone (LH) and follicle-stimulating hormone (FSH). LH surge triggers ovulation, while FSH stimulates follicular growth and estrogen production. Estrogen levels peak, and then decline, leading to a surge in LH, causing ovulation.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify the key regulators of the ovarian cycle, which are the hypothalamic-pituitary-ovarian axis and the hormones involved.
**Option B:** This option is incorrect because it is too broad and does not accurately describe the process of ovulation and follicular growth.
**Option C:** This option is incorrect because it is incomplete and does not include the critical role of FSH in follicular growth and estrogen production.

**Clinical Pearl / High-Yield Fact**
The LH surge is a critical event in the ovarian cycle, occurring approximately 36-40 hours before ovulation, and its timing is essential for the coordination of ovulation and fertilization.

**Correct Answer:** D.