**Core Concept**
Gynaecomastia and infertility in a man are manifestations of an imbalance in sex hormones, specifically an increase in estrogen relative to testosterone. This imbalance can be caused by various factors, including hormonal disorders, medications, and certain medical conditions.

**Why the Correct Answer is Right**
The correct answer is related to the pathophysiology of gynaecomastia and infertility. Gynaecomastia is characterized by the growth of breast tissue in males, which is often associated with an estrogen-to-testosterone ratio imbalance. In this case, the patient's symptoms suggest an excess of estrogen, which can be caused by a variety of factors, including testicular failure, liver disease, or certain medications that increase estrogen levels. For example, nonsteroidal anti-androgens (NSAIDs) such as spironolactone can bind to androgen receptors, leading to a decrease in testosterone levels and an increase in estrogen levels.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not directly address the hormonal imbalance causing gynaecomastia and infertility.
**Option B:** This option is incorrect because it is a treatment for hypogonadism, not a cause of gynaecomastia and infertility.
**Option C:** This option is incorrect because it is a cause of hypogonadism, not gynaecomastia and infertility.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that gynaecomastia can be a sign of underlying liver disease, particularly cirrhosis, due to the increased conversion of androgens to estrogens by the liver.

**Correct Answer:** Klinefelter syndrome is a genetic condition characterized by the presence of an extra X chromosome in males (XXY), leading to infertility and gynaecomastia due to testicular failure and hormonal imbalance.