**Core Concept**
The cardinal signs of inflammation are a group of classic symptoms that describe the changes that occur in the affected tissue due to an inflammatory response. These signs are a result of the complex interplay between various chemical mediators, immune cells, and other factors that contribute to the inflammatory process.

**Why the Correct Answer is Right**
Cyanosis, or the bluish discoloration of the skin and mucous membranes, is not typically considered one of the cardinal signs of inflammation. The correct signs of inflammation are Rubor (redness), Tumor (swelling), Calor (increased heat), and Dolor (pain), also known as the "4 C's" of inflammation. These signs are a result of the increased blood flow and vascular permeability that occur during inflammation.

**Why Each Wrong Option is Incorrect**
**Option A:** Rubor is indeed one of the cardinal signs of inflammation, characterized by the increased blood flow and vascular permeability that lead to redness and warmth of the affected area.
**Option B:** Tumor is also a cardinal sign of inflammation, referring to the swelling that results from the accumulation of fluid and inflammatory cells in the affected tissue.
**Option C:** Color is not directly mentioned as one of the cardinal signs of inflammation, but it is implied by the sign of Rubor. However, the term "Color" is too vague and does not accurately represent the specific signs of inflammation.

**Clinical Pearl / High-Yield Fact**
Remember the "4 C's" of inflammation: Rubor (redness), Tumor (swelling), Calor (increased heat), and Dolor (pain). These signs are a hallmark of the inflammatory response and are essential to recognize in clinical practice.

**✓ Correct Answer: D. Cyanosis**