**Core Concept**
Rho kinase inhibitors are a class of drugs that block the action of Rho kinase enzyme, which plays a crucial role in smooth muscle contraction, platelet activation, and cell proliferation. By inhibiting Rho kinase, these drugs can reduce blood pressure, prevent blood clots, and inhibit tumor growth.

**Why the Correct Answer is Right**
Fasudil is a potent Rho kinase inhibitor that works by competing with RhoA for binding to Rho kinase, thereby preventing the activation of the enzyme. This results in the inhibition of smooth muscle contraction, platelet aggregation, and cell proliferation. Fasudil has been shown to have therapeutic effects in the treatment of conditions such as hypertension, cerebral vasospasm, and pulmonary hypertension.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it is not a known Rho kinase inhibitor.
**Option B:** This option is incorrect because it is not a Rho kinase inhibitor; it is actually a calcium channel blocker.
**Option C:** This option is incorrect because it is not a Rho kinase inhibitor; it is actually a phosphodiesterase inhibitor.

**Clinical Pearl / High-Yield Fact**
Fasudil is also known as an "endothelial-derived relaxing factor" (EDRF) that has vasodilatory properties and is used to treat cerebral vasospasm following subarachnoid hemorrhage.

**Correct Answer:** C. Fasudil