**Core Concept**
Alveolitis, also known as interstitial lung disease (ILD), refers to a group of disorders characterized by inflammation and fibrosis of the lung interstitium, leading to impaired gas exchange and lung function. The pathophysiology involves damage to the alveolar-capillary membrane, resulting in impaired diffusion of oxygen and carbon dioxide.

**Why the Correct Answer is Right**
Alveolitis is characterized by the presence of inflammatory cells, such as macrophages and lymphocytes, in the lung interstitium. This inflammation leads to the release of pro-inflammatory cytokines, which in turn cause damage to the alveolar epithelial cells and the pulmonary capillary endothelium. The resulting fibrosis can lead to the obliteration of the alveolar spaces and the formation of honeycombing, a hallmark of advanced ILD.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is likely a feature of alveolitis, as it involves inflammation and damage to the lung interstitium, which is a hallmark of the disease.
**Option B:** This option is also a feature of alveolitis, as it involves the release of pro-inflammatory cytokines and the activation of immune cells in the lung interstitium.
**Option C:** This option is a feature of alveolitis, as it involves the formation of fibrosis and the obliteration of the alveolar spaces, which is a hallmark of advanced ILD.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that the clinical presentation of alveolitis can be non-specific, and patients may present with symptoms such as dyspnea, cough, and fatigue. A high index of suspicion is necessary to diagnose ILD, and imaging studies such as high-resolution computed tomography (HRCT) are crucial in establishing the diagnosis.

**Correct Answer: D.**