**Core Concept**
Estrogen production in the menstrual cycle is primarily governed by the **hypothalamic-pituitary-ovarian axis**, involving a complex interplay of hormones. The **follicular phase** is characterized by the growth of follicles in the ovaries, which produce **estrogen**.

**Why the Correct Answer is Right**
The correct answer choice is related to the fact that estrogen levels surge during the **follicular phase**, peaking right before ovulation. This increase in estrogen is due to the growth and maturation of **graafian follicles** under the influence of **FSH (follicle-stimulating hormone)**.

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because it doesn't accurately describe the primary phase associated with significant estrogen production.
**Option B:** Incorrect as it misrepresents the hormonal dynamics during the menstrual cycle.
**Option C:** Incorrect because it fails to acknowledge the role of follicular development in estrogen production.
**Option D:** Incorrect as it inaccurately represents the timing and regulation of estrogen production.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that **estrogen** plays a crucial role in the **proliferative phase** of the menstrual cycle, influencing the growth and thickening of the **endometrium**.

**Correct Answer:** D. Estrogen is produced in large amounts during the follicular phase of the menstrual cycle.