**Core Concept**
Hot flushes in postmenopausal women are a result of decreased estrogen levels, leading to vasomotor instability. The hypothalamus plays a key role in regulating body temperature, and estrogen deficiency disrupts this process, causing hot flushes.

**Why the Correct Answer is Right**
The administration of estrogen replacement therapy (ERT) or selective estrogen receptor modulators (SERMs) can relieve hot flushes in postmenopausal women. Estrogen acts on estrogen receptors in the hypothalamus, which helps to regulate body temperature. SERMs, such as tamoxifen, mimic the beneficial effects of estrogen on hot flushes while having minimal effects on the endometrium. This helps to reduce hot flushes without increasing the risk of endometrial cancer.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because non-steroidal anti-inflammatory drugs (NSAIDs) are not effective in relieving hot flushes. While NSAIDs can help with other symptoms of menopause, such as dysmenorrhea, they do not address the underlying cause of hot flushes.

**Option B:** This option is incorrect because selective serotonin reuptake inhibitors (SSRIs) are not primarily used to treat hot flushes. While SSRIs can be used to treat other symptoms of menopause, such as depression, they are not effective in relieving hot flushes.

**Option C:** This option is incorrect because gabapentin is not a first-line treatment for hot flushes. While gabapentin can be used to treat other symptoms of menopause, such as neuropathic pain, it is not effective in relieving hot flushes.

**Clinical Pearl / High-Yield Fact**
It is essential to note that hormone replacement therapy (HRT) should be individualized and considered on a case-by-case basis, taking into account the patient's medical history, risk factors, and personal preferences.

**Correct Answer:** C. Gabapentin