**Core Concept**
Asthma is a chronic inflammatory disease of the airways characterized by **reversible airflow obstruction**, **airway hyperresponsiveness**, and **inflammation**. The morphology of asthma involves various pathological changes in the airways.

**Why the Correct Answer is Right**
The correct answer involves options that accurately describe the morphology of asthma. **Charcot-Leyden crystals**, found in option a, are associated with eosinophilic inflammation, a hallmark of asthma. **Intermittent asthma** being more responsive to **bronchodilator therapy**, as mentioned in option d, aligns with the reversible nature of asthma. **Hypersensitive lung**, option e, refers to the airway hyperresponsiveness seen in asthma.

**Why Each Wrong Option is Incorrect**
**Option B:** Irreversible changes are more characteristic of chronic obstructive pulmonary disease (COPD) rather than asthma. **Option C:** Asthma typically involves smaller airways rather than larger ones.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that asthma is characterized by its reversibility and airway hyperresponsiveness, making **bronchodilator therapy** effective, especially in intermittent cases.

**Correct Answer:** D. e