**Core Concept:** Surfactant is a complex mixture of lipids and proteins secreted by type II alveolar cells in the lungs. Its primary function is to reduce surface tension at the air-liquid interface in the alveoli, allowing for improved gas exchange and prevention of alveolar collapse.

**Why the Correct Answer is Right:** Surfactant contains phospholipids, proteins, and triglycerides, which together make up the majority of its composition. This unique mixture helps to stabilize the alveolar structure and prevents alveolar collapse, promoting proper gas exchange.

**Why Each Wrong Option is Incorrect:**

A. This option is incorrect because surfactant does not primarily consist of carbohydrates. The correct answer mentions phospholipids, proteins, and triglycerides.

B. This option is incorrect because surfactant does not primarily contain enzymes. Surfactant is primarily composed of lipids and proteins, such as surfactant proteins (SP-A, SP-B, SP-C, and SP-D) and phospholipids.

C. This option is incorrect because surfactant does not primarily consist of lipids. The correct answer mentions phospholipids, proteins, and triglycerides.

D. This option is incorrect because surfactant does not primarily contain cholesterol. Surfactant is primarily composed of phospholipids, proteins, and triglycerides, with a lesser amount of cholesterol, which helps to stabilize the phospholipid bilayers.

**Clinical Pearl:** Surfactant replacement therapy is a treatment for respiratory distress syndrome (RDS) in premature infants, a condition characterized by impaired surfactant production or function. This therapy involves administering exogenous surfactant to maintain proper lung function and improve oxygenation.