**Core Concept**
Menorrhagia, a condition characterized by abnormally heavy or prolonged menstrual bleeding, can be caused by various factors, including hormonal imbalances, uterine fibroids, and coagulopathy. In this scenario, the patient's hypertension and multiparity suggest a possible underlying coagulopathy or endocrine disorder.

**Why the Correct Answer is Right**
The best treatment for menorrhagia in this patient would involve addressing the underlying cause, which is likely related to her hypertension and hormonal imbalances. **Combined Oral Contraceptives (COCs)** are a suitable option for managing menorrhagia, as they regulate menstrual cycles and reduce blood loss. COCs work by suppressing the hypothalamic-pituitary-ovarian axis, leading to a decrease in estrogen and progesterone levels. This reduction in hormone levels helps to decrease uterine contraction and shedding, ultimately reducing menstrual bleeding.

**Why Each Wrong Option is Incorrect**
**Option A:** **Progestin-only pills** may not be as effective in reducing menstrual bleeding as COCs, as they do not suppress estrogen levels to the same extent.
**Option B:** **Non-steroidal anti-inflammatory drugs (NSAIDs)** can help alleviate symptoms of menorrhagia by reducing prostaglandin levels, but they do not address the underlying cause of the condition.
**Option C:** **Hysterectomy** is a more invasive option that should be considered only after other treatments have failed, and it is not the best initial treatment for this patient.

**Clinical Pearl / High-Yield Fact**
When managing menorrhagia, it's essential to consider the underlying cause and tailor treatment accordingly. COCs are a good option for patients with hormonal imbalances, while NSAIDs may be useful for patients with coagulopathy or uterine fibroids.

**Correct Answer:** D.