**Core Concept**
The question tests the student's knowledge of physical properties of anesthetic agents, specifically boiling points. **Inhalational anesthetics** have distinct boiling points, which influence their usage and delivery systems.

**Why the Correct Answer is Right**
Anesthetic agents with high boiling points are typically used in vaporizers specifically designed to deliver precise concentrations of these agents. One such agent is **isoflurane**, which has a boiling point of 48.5°C, but another agent, **sevoflurane**, has a lower boiling point. However, considering the options and common anesthetics, **halothane** has a boiling point close to but not exceeding 75°C, yet it's known that **desflurane** has a very low boiling point. The correct answer likely refers to an agent like **sevoflurane** or another with a boiling point above 75°C, but given common options, it seems there might be a misunderstanding in the question as presented.

**Why Each Wrong Option is Incorrect**
**Option A:** Without specific details on the options provided, we can't directly address why each is incorrect based on their boiling points.
**Option B:** Similarly, without the specific agent, we can't comment on its boiling point.
**Option C:** And **Option D:** lack specific references to known anesthetic agents' boiling points.

**Clinical Pearl / High-Yield Fact**
It's crucial to remember that the **boiling point** of an anesthetic agent determines the type of vaporizer used. Agents with lower boiling points require specialized vaporizers to prevent excessive delivery.

**Correct Answer:** Correct Answer: D. Isoflurane