**Core Concept**
Atenolol is a beta-1 selective adrenergic receptor antagonist used in the management of hypertension, angina pectoris, and certain cardiac arrhythmias. Its pharmacokinetic properties, particularly its excretion pathway, are crucial for understanding its clinical effects and potential interactions.

**Why the Correct Answer is Right**
Atenolol is predominantly excreted by the kidneys, primarily through the glomerular filtration route. This is because atenolol is a relatively polar, water-soluble compound that does not undergo significant hepatic metabolism. As a result, its elimination half-life is relatively long, allowing for once-daily dosing. The renal excretion of atenolol is also influenced by its binding to plasma proteins, which affects its volume of distribution and clearance.

**Why Each Wrong Option is Incorrect**
**Option A:** Renal excretion is the primary route of elimination for atenolol, but hepatic metabolism is not a significant factor in its elimination.
**Option B:** While atenolol does have some degree of biliary excretion, this is not its predominant route of elimination.
**Option C:** Atropine is an anticholinergic agent that has a different mechanism of action and excretion pathway compared to atenolol.

**Clinical Pearl / High-Yield Fact**
In patients with renal impairment, the elimination of atenolol may be slowed, leading to increased plasma concentrations and potential toxicity. This highlights the importance of dose adjustment in patients with compromised renal function.

**Correct Answer: B. Biliary excretion is a minor route of elimination for atenolol, but renal excretion is the primary route.