## Core Concept
Acute phase reactants are proteins whose plasma concentrations increase or decrease in response to inflammation. This response is part of the acute phase reaction, which occurs in the early stages of inflammation. These proteins are produced by the liver in response to inflammatory cytokines.

## Why the Correct Answer is Right
The correct answer includes fibrinogen, haptoglobin, and can be inferred to include options that are known acute phase reactants. Fibrinogen (b) and haptoglobin (c) are indeed acute phase reactants. Their levels increase during acute inflammation.

## Why Each Wrong Option is Incorrect
- **Option A: Albumin** - This is incorrect because albumin levels actually decrease during acute inflammation. It is a negative acute phase reactant.
- **Option D: Gammaglobulin** - While gammaglobulins (antibodies) can increase in various inflammatory and immune responses, they are not considered part of the acute phase response in the same immediate context as fibrinogen and haptoglobin.

## Clinical Pearl / High-Yield Fact
A key point to remember is that during acute inflammation, there's an increase in certain proteins (positive acute phase reactants) like **fibrinogen**, **haptoglobin**, and **C-reactive protein**, and a decrease in others (negative acute phase reactants) like **albumin**. This change can affect various laboratory tests.

## Correct Answer: B.