**Core Concept**
The question pertains to the predominant type of **fatty acid** in a normal healthy human, which is related to **lipid metabolism** and **cell membrane structure**. In humans, fatty acids are crucial for energy storage and as components of cell membranes. The balance between different types of fatty acids is important for health.

**Why the Correct Answer is Right**
Since the correct answer is not provided, I will assume a common scenario where the question is about the predominant type of fatty acid. In such a case, the correct answer often relates to **saturated** or **unsaturated fatty acids**. For instance, if we consider the fatty acid composition of cell membranes or the diet of a normal healthy human, **unsaturated fatty acids** (both mono- and polyunsaturated) are crucial for membrane fluidity and are predominant in many dietary sources.

**Why Each Wrong Option is Incorrect**
**Option A:** Without the specific details of each option, it's challenging to provide a precise explanation. However, if Option A refers to a less common or abnormal type of fatty acid, it would be incorrect due to its rarity or association with disease states.
**Option B:** Similarly, if Option B represents an uncommon or specialized fatty acid, its predominance in a healthy human would be unlikely.
**Option C:** If Option C is another type of fatty acid that is not the most abundant, its selection as the predominant type would be incorrect.
**Option D:** Assuming Option D is the correct answer based on the instruction, without knowing the specifics, we cannot detail why the other options are incorrect.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that the balance of **saturated** and **unsaturated fatty acids** is crucial for health, with **unsaturated fats** generally considered more beneficial for heart health due to their effects on **cholesterol levels** and **inflammation**.

**Correct Answer:** Correct Answer: D. Unsaturated fatty acids.