**Core Concept**
Prince Metel's angina, also known as Prinzmetal's angina, is a variant of angina pectoris caused by transient, coronary artery vasospasm. This condition is characterized by episodes of chest pain at rest, often occurring at night, due to the temporary narrowing of the coronary arteries.

**Why the Correct Answer is Right**
The correct answer is a drug that exacerbates or induces coronary artery vasospasm, which would worsen the symptoms of Prince Metel's angina. **Nitrates**, such as isosorbide dinitrate, typically relieve angina by dilating coronary arteries and reducing myocardial oxygen demand. However, in patients with Prince Metel's angina, nitrates can paradoxically worsen vasospasm by releasing nitric oxide, a potent vasodilator that can also relax and reduce the tone of the smooth muscle cells in the coronary arteries, leading to further vasospasm.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because beta-blockers, such as propranolol, are actually contraindicated in Prince Metel's angina as they can worsen the condition by reducing the vasodilatory effects of endogenous catecholamines and potentially increasing the frequency and severity of vasospastic episodes.
**Option B:** This option is incorrect because calcium channel blockers, such as verapamil, are actually the preferred treatment for Prince Metel's angina as they can help prevent vasospasm by inhibiting the influx of calcium ions into the smooth muscle cells of the coronary arteries.
**Option C:** This option is incorrect because ranolazine, an antianginal medication, is actually used to treat chronic angina and does not exacerbate or induce coronary artery vasospasm.

**Clinical Pearl / High-Yield Fact**
In patients with Prince Metel's angina, it is essential to avoid nitrates as they can worsen vasospasm and increase the risk of myocardial infarction. Calcium channel blockers, such as verapamil and diltiazem, are the preferred treatment for this condition.

**Correct Answer:** A.