**Core Concept**
Oral contraceptives work by disrupting the normal menstrual cycle, primarily through the suppression of gonadotropin secretion. They exert their effects by affecting the hypothalamic-pituitary-ovarian axis, thereby preventing ovulation and altering the endometrium.

**Why the Correct Answer is Right**
The primary mechanism of action of oral contraceptives involves the inhibition of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) secretion from the anterior pituitary gland. This is achieved through the negative feedback effects of estrogen and progesterone, which are present in oral contraceptives. The reduction in FSH and LH secretion leads to a decrease in estrogen production by the ovaries, ultimately preventing the growth and maturation of follicles and ovulation.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not accurately describe the primary mechanism of action of oral contraceptives. While certain oral contraceptives may have some androgenic effects, this is not their primary mode of action.
**Option B:** This option is incorrect because it is too broad and does not specifically address the mechanism of action of oral contraceptives. Many factors can contribute to the regulation of the menstrual cycle, but the primary mechanism of oral contraceptives involves the suppression of gonadotropin secretion.
**Option C:** This option is incorrect because it is not a well-defined or recognized mechanism of action for oral contraceptives. While certain medications may have effects on the autonomic nervous system, this is not a primary mechanism of action for oral contraceptives.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that oral contraceptives can have various side effects, including thromboembolic events, and are contraindicated in women with a history of deep vein thrombosis or pulmonary embolism. Additionally, certain oral contraceptives may have a higher risk of breast cancer, and women with a family history of breast cancer should use caution when selecting a contraceptive method.

**Correct Answer: C. Inhibition of gonadotropin secretion, preventing ovulation and altering the endometrium.**