**Core Concept**
The question tests the understanding of antihypertensive medication use in the elderly, particularly in the setting of severe hypertension. **Hypertension management** in this population requires careful consideration of the potential for orthostatic hypotension and the impact of various antihypertensive agents on this risk.

**Why the Correct Answer is Right**
Given the lack of specific options, the general principle is that medications which can cause a rapid decrease in blood pressure or those that are known to increase the risk of orthostatic hypotension should be used cautiously. This includes certain **vasodilators**, **alpha-blockers**, and **diuretics** in high doses.

**Why Each Wrong Option is Incorrect**
**Option A:** Without specifics, it's hard to comment, but generally, **beta-blockers** can be used in hypertension, though they might not be the first choice in the elderly due to potential side effects.
**Option B:** Similarly, without the option text, we can't directly address why it might be incorrect, but **calcium channel blockers** are often well-tolerated in the elderly.
**Option C:** Again, lacking the specific option, typically **ACE inhibitors** are used with caution but can be beneficial in the elderly with hypertension.
**Option D:** This option is also unspecified, but **direct vasodilators** like hydralazine can be used in severe hypertension, though with careful monitoring.

**Clinical Pearl / High-Yield Fact**
In managing severe hypertension in the elderly, it's crucial to avoid using medications that could exacerbate **orthostatic hypotension**, as this can increase the risk of falls and other complications.

**Correct Answer:** D. Direct vasodilators like hydralazine.