**Core Concept**
Pulmonary surfactant is a complex mixture of phospholipids and proteins that reduces surface tension within the alveoli, thereby preventing lung collapse during expiration. This surfactant is crucial for maintaining lung compliance and facilitating gas exchange.

**Why the Correct Answer is Right**
Pulmonary surfactant is primarily produced and secreted by type II pneumocytes, also known as type II alveolar cells. These cells are located in the alveolar walls and produce surfactant through a process involving the enzyme phospholipid transfer protein (PLTP) and the surfactant protein B (SP-B) and C (SP-C). The surfactant is then secreted into the alveolar space, where it reduces surface tension and facilitates lung expansion.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because while alveolar macrophages play a role in clearing surfactant from the alveoli, they do not produce surfactant.
**Option B:** This option is incorrect because Clara cells, also known as club cells, are involved in producing surfactant protein D (SP-D), but they do not produce the majority of pulmonary surfactant.
**Option C:** This option is incorrect because fibroblasts are involved in producing extracellular matrix components, but they do not produce pulmonary surfactant.

**Clinical Pearl / High-Yield Fact**
Pulmonary surfactant dysfunction is a key component of neonatal respiratory distress syndrome (RDS), which is often seen in premature infants. The use of surfactant replacement therapy has significantly improved outcomes in these patients.

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