**Core Concept**
Flunarizine is a calcium channel blocker with a unique pharmacological profile, primarily used for its anti-migraine properties. It is a selective blocker of L-type calcium channels, but its effects on vascular smooth muscle are more pronounced.

**Why the Correct Answer is Right**
Flunarizine's mechanism of action involves the blockade of L-type calcium channels in the cerebral blood vessels, leading to vasodilation and reduced intracranial pressure. This effect is primarily responsible for its anti-migraine activity. In contrast, its effects on cardiac muscle are minimal, making it less effective for treating angina pectoris. Flunarizine's selectivity for cerebral blood vessels is due to its higher affinity for L-type calcium channels in these tissues.

**Why Each Wrong Option is Incorrect**
**Option A:** Verapamil is a non-selective calcium channel blocker that affects both cardiac and smooth muscle, making it effective for treating angina pectoris. Its mechanism of action involves blockade of L-type calcium channels in cardiac muscle, leading to reduced myocardial contractility and vascular resistance.
**Option B:** Diltiazem is another non-selective calcium channel blocker with effects on both cardiac and smooth muscle. Its use in treating angina pectoris is due to its ability to reduce myocardial oxygen demand and increase coronary blood flow.
**Option D:** Amlodipine is a dihydropyridine calcium channel blocker that primarily affects vascular smooth muscle, leading to vasodilation and reduced blood pressure. While it is used to treat hypertension and angina pectoris, its effects on cardiac muscle are minimal.

**Clinical Pearl / High-Yield Fact**
Flunarizine's selective blockade of L-type calcium channels in cerebral blood vessels makes it an effective treatment for migraines. However, its minimal effects on cardiac muscle make it less suitable for treating angina pectoris.

✓ Correct Answer: C. Flunarizine