**Core Concept**
Nonselective beta blockers inhibit both beta-1 and beta-2 adrenergic receptors, leading to a range of pharmacological effects. These agents are used in various clinical settings, including hypertension, angina, and certain arrhythmias.

**Why the Correct Answer is Right**
Nonselective beta blockers like propranolol have additional actions beyond beta blockade, including:
- Anticholinergic effects due to their ability to block muscarinic receptors
- Membrane-stabilizing effects, which can influence the cardiac action potential
- Inhibition of the renin-angiotensin-aldosterone system (RAAS), contributing to their antihypertensive effects
- Interaction with other receptors and ion channels, such as the alpha-1 adrenergic receptor and the slow calcium channel

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect, as propranolol is a classic example of a nonselective beta blocker with additional actions.
**Option B:** Incorrect, as carvedilol is a nonselective beta blocker that also has alpha-1 blocking activity and antioxidant properties.
**Option C:** Incorrect, as nadolol is a nonselective beta blocker with a long duration of action and additional membrane-stabilizing effects.

**Clinical Pearl / High-Yield Fact**
Nonselective beta blockers can be useful in patients with certain types of asthma, as they can reduce the frequency of asthma attacks by blocking beta-2 receptors in the airways.

**Correct Answer: A.**