## **Core Concept**
Gynaecomastia is a condition characterized by the enlargement of breast tissue in males, often caused by an imbalance of sex hormones, specifically an increase in estrogen relative to testosterone. This condition can be drug-induced among other causes.

## **Why the Correct Answer is Right**
The correct answer, , is associated with spironolactone, which is a potassium-sparing diuretic used primarily in the treatment of heart failure, hypertension, and conditions like primary aldosteronism. Spironolactone acts as an antagonist of the androgen receptor, which can lead to an imbalance in the hormonal milieu, favoring the effects of estrogen over androgens. This hormonal imbalance can cause gynaecomastia.

## **Why Each Wrong Option is Incorrect**
* **Option A:** - This option does not directly relate to a commonly known cause of gynaecomastia.
* **Option B:** - This option does not specify a drug commonly associated with gynaecomastia.
* **Option D:** - This option does not directly correspond with a well-known drug-induced cause of gynaecomastia.

## **Clinical Pearl / High-Yield Fact**
A key clinical pearl is that drugs causing gynaecomastia often do so by either increasing estrogen levels or decreasing androgen levels/effects. Spironolactone is a classic example of a drug that causes gynaecomastia due to its anti-androgenic effects.

## **Correct Answer:** . Spironolactone