**Core Concept**
The management of asthma patients requires careful consideration of anesthetic agents to prevent bronchospasm and ensure a safe anesthetic experience. Inhaled anesthetics can cause bronchodilation, but some have a more favorable effect on asthma patients than others.

**Why the Correct Answer is Right**
The correct answer is **C. Isoflurane**. Isoflurane is an inhaled anesthetic that provides bronchodilation through the activation of potassium channels in smooth muscle cells, leading to relaxation of bronchial muscles and improved lung function. Isoflurane also has a low risk of causing histamine release, which can exacerbate bronchospasm.

**Why Each Wrong Option is Incorrect**
**Option A:** Halothane is an inhaled anesthetic that can cause histamine release, leading to bronchospasm and increased airway resistance, making it a poor choice for asthma patients.

**Option B:** Sevoflurane can cause airway irritation and bronchospasm, especially in patients with a history of asthma.

**Option D:** Nitrous oxide can cause bronchodilation, but it is often used in combination with other anesthetics and may not provide adequate bronchodilation on its own.

**Clinical Pearl / High-Yield Fact**
Isoflurane is often considered the anesthetic of choice for asthma patients because of its favorable effect on bronchial smooth muscle and low risk of causing histamine release.

**Correct Answer: C. Isoflurane**