**Core Concept**
In the elderly population, the treatment of hypertension requires careful consideration of various factors, including comorbidities, polypharmacy, and decreased renal function. The primary goal of treatment is to reduce the risk of cardiovascular events while minimizing the risk of adverse effects.

**Why the Correct Answer is Right**
The American College of Cardiology and the American Heart Association recommend starting with a low dose of a renin-angiotensin-aldosterone system (RAAS) inhibitor, such as an ACE inhibitor or an ARB, in elderly patients with hypertension. This is because RAAS inhibitors have been shown to reduce the risk of cardiovascular events and have a more favorable renal profile compared to other antihypertensive agents. In addition, RAAS inhibitors are less likely to exacerbate orthostatic hypotension, which is a common concern in the elderly population.

**Why Each Wrong Option is Incorrect**
**Option A:** Starting with a high dose of a diuretic, such as a thiazide or loop diuretic, is not recommended in the elderly population due to the risk of hypokalemia, hyponatremia, and dehydration.
**Option B:** Beta-blockers may be used in elderly patients with hypertension, but they are not the first-line treatment due to their potential to worsen orthostatic hypotension and mask symptoms of hypoglycemia.
**Option C:** Calcium channel blockers can be used in elderly patients with hypertension, but they are not the preferred initial treatment due to their potential to cause peripheral edema and gastrointestinal side effects.
**Option D:** Direct vasodilators, such as hydralazine, are not recommended as first-line treatment in elderly patients with hypertension due to their potential to cause reflex tachycardia and worsening of heart failure.

**Clinical Pearl / High-Yield Fact**
It is essential to remember that the elderly population may experience age-related changes in pharmacokinetics and pharmacodynamics, which can affect the response to antihypertensive medications. Therefore, it is crucial to start with a low dose and titrate upwards gradually to minimize the risk of adverse effects.

**Correct Answer: A. Starting with a low dose of a renin-angiotensin-aldosterone system (RAAS) inhibitor.**