## Core Concept
The question tests the understanding of **adrenergic receptor selectivity**, specifically focusing on drugs that act on **beta receptors**. Adrenergic receptors are targeted by various drugs for treating conditions like hypertension, asthma, and heart failure. Beta receptors are further subdivided into β1, β2, and β3 receptors, each having different tissue distributions and physiological effects.

## Why the Correct Answer is Right
The correct answer, **Propranolol** is not actually selective for beta receptors as it is a non-selective beta blocker. However, assuming there's a mix-up and the intent was to identify a drug with beta receptor selectivity:
- **Propranolol** blocks both β1 and β2 receptors non-selectively.
- A **beta-selective** drug would primarily target either β1 (e.g., **Metoprolol**) or β2 (e.g., **Salbutamol**) receptors.

## Why Each Wrong Option is Incorrect
- **Option A:** Without the actual drug name provided, we can't assess its receptor selectivity directly.
- **Option B:** Similarly, without specifics, we can't evaluate its action on beta receptors.
- **Option D:** Likewise, the drug name is needed to determine its pharmacological profile.

## Clinical Pearl / High-Yield Fact
A key point to remember is that **β1 receptors** are predominantly found in the heart, where their blockade can reduce heart rate and contractility, making **β1-selective blockers** like **Metoprolol** useful in treating hypertension and heart failure. **β2 receptors** are mainly in smooth muscle, where their activation causes relaxation, making **β2 agonists** like **Salbutamol** effective for asthma.

## Correct Answer: C. Propranolol