**Core Concept**
Ovulation is a critical phase in the menstrual cycle where a mature ovum is released from the dominant follicle in the ovary. This process is regulated by a complex interplay between the hypothalamic-pituitary-gonadal axis, resulting in the surge of luteinizing hormone (LH) that triggers ovulation.

**Why the Correct Answer is Right**
In a woman with a 28-day menstrual cycle, ovulation typically occurs around day 14. This is because the follicular phase, which is characterized by the growth and maturation of follicles in the ovaries, usually lasts for 14 days. The LH surge, which is triggered by the peak of follicle-stimulating hormone (FSH), occurs approximately 36-40 hours before ovulation, leading to the rupture of the dominant follicle and the release of the ovum. The resulting corpus luteum then produces progesterone, which prepares the uterus for a potential pregnancy.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the exact day of ovulation can vary depending on individual factors, such as age, health status, and hormonal balance. However, in a typical 28-day cycle, ovulation usually occurs around day 14.
**Option B:** This option is incorrect because the follicular phase can last anywhere from 10 to 20 days, depending on the individual's menstrual cycle length.
**Option C:** This option is incorrect because the luteal phase, which is the period after ovulation, typically lasts for 14 days, not before ovulation.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that ovulation can occur at any time within a 5-day window, making it challenging to pinpoint the exact day of ovulation. However, knowing the typical 28-day cycle and the follicular and luteal phases can help healthcare providers estimate the timing of ovulation and provide guidance on fertility and reproductive health.

**Correct Answer: D. Day 14**