**Core Concept**
Prostaglandins are a group of lipids made by the enzyme prostaglandin synthase from arachidonic acid, a polyunsaturated fatty acid derived from cell membrane phospholipids. This process involves a complex series of enzyme-catalyzed reactions known as the eicosanoid pathway. The resulting prostaglandins play a crucial role in various physiological and pathological processes, including inflammation, pain, and fever.

**Why the Correct Answer is Right**
Prostaglandins are synthesized from arachidonic acid through the action of the enzyme cyclooxygenase (COX), which is the rate-limiting step in the production of prostaglandins. This enzyme catalyzes the conversion of arachidonic acid into prostaglandin H2, which is then further converted into various prostaglandins by other enzymes. The prostaglandin synthase enzyme is responsible for this conversion, making arachidonic acid the primary precursor molecule for prostaglandin synthesis.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because prostaglandins are not derived from cholesterol, which is the precursor molecule for the synthesis of steroid hormones, not prostaglandins.
* **Option B:** This option is incorrect because arachidonic acid is not converted directly into prostaglandins without the involvement of the enzyme cyclooxygenase (COX).
* **Option D:** This option is incorrect because eicosatetraenoic acid (EPA) is a different polyunsaturated fatty acid that is a precursor molecule for the synthesis of eicosanoids, but not specifically prostaglandins.

**Clinical Pearl / High-Yield Fact**
It's essential to remember that nonsteroidal anti-inflammatory drugs (NSAIDs) work by inhibiting the enzyme cyclooxygenase (COX), which is responsible for the synthesis of prostaglandins from arachidonic acid. This inhibition leads to a reduction in the production of prostaglandins, resulting in decreased inflammation and pain.

**Correct Answer:** C.