**Core Concept**
Cardiac remodeling in congestive heart failure (CHF) refers to the structural and functional changes in the heart that occur in response to prolonged pressure overload or volume overload. This process involves hypertrophy of cardiac myocytes, fibrosis, and changes in the extracellular matrix, ultimately leading to decreased cardiac function.

**Why the Correct Answer is Right**
The correct answer is a drug that inhibits the renin-angiotensin-aldosterone system (RAAS), which plays a crucial role in cardiac remodeling. By inhibiting the conversion of angiotensin I to angiotensin II, this drug reduces vasoconstriction, sodium retention, and fibrosis, ultimately leading to decreased cardiac remodeling and improved cardiac function. Enalapril, a converting enzyme inhibitor (ACEI), is a classic example of such a drug.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because beta-blockers, while beneficial in CHF, primarily work by reducing heart rate and contractility, rather than directly inhibiting cardiac remodeling.
* **Option B:** This option is incorrect because diuretics, while useful in managing symptoms of CHF, do not directly influence cardiac remodeling.
* **Option C:** This option is incorrect because calcium channel blockers, while useful in certain cardiovascular conditions, do not have a direct effect on cardiac remodeling in CHF.

**Clinical Pearl / High-Yield Fact**
The RAAS system is a key player in cardiac remodeling, and inhibiting this system with ACE inhibitors or ARBs is a cornerstone of CHF management.

**Correct Answer: A. Enalapril**