**Core Concept**
Surfactant is a complex mixture of phospholipids and proteins that lines the alveoli of the lungs, reducing surface tension and facilitating gas exchange. It is essential for maintaining lung compliance and preventing alveolar collapse during expiration.

**Why the Correct Answer is Right**
Surfactant is primarily produced by type II pneumocytes, also known as Clara cells, in the distal airspaces of the lungs. These cells synthesize and secrete surfactant into the alveolar space, where it can act to reduce surface tension. The production of surfactant is regulated by hormones such as cortisol and thyroid-stimulating hormone, as well as by local factors such as oxygen levels and stretch.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because while alveolar macrophages play a role in clearing surfactant from the alveolar space, they are not responsible for producing it.
**Option B:** This option is incorrect because Clara cells, also known as club cells, are a subset of non-ciliated epithelial cells found in the bronchioles, but they are not the primary source of surfactant.
**Option C:** This option is incorrect because while fibroblasts are involved in the production of extracellular matrix components, they are not responsible for producing surfactant.

**Clinical Pearl / High-Yield Fact**
Respiratory distress syndrome (RDS) in preterm infants is often caused by a deficiency of surfactant, leading to alveolar collapse and impaired gas exchange. This condition can be treated with exogenous surfactant administration.

**Correct Answer: C. Type II pneumocytes.**