**Core Concept**
Acute phase reactants are proteins whose plasma concentrations increase or decrease in response to inflammation, representing a nonspecific response to tissue damage. This response is mediated by **cytokines** such as interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha).

**Why the Correct Answer is Right**
The correct answer is based on the understanding that acute phase reactants typically include proteins like **C-reactive protein (CRP)**, **fibrinogen**, **ceruloplasmin**, and **haptoglobin**, which increase in response to inflammation.

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because it's not provided.
**Option B:** Incorrect because it's not provided.
**Option C:** Incorrect because it's not provided.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that **albumin** levels typically decrease during the acute phase response, making it a negative acute phase reactant.

**Correct Answer:** D. Albumin.