**Core Concept**
Myofibroblast is a type of cell that plays a crucial role in wound healing and fibrosis. It is characterized by its expression of alpha-smooth muscle actin (α-SMA) and its ability to contract, which helps to close wounds and reorganize tissue architecture.

**Why the Correct Answer is Right**
Myofibroblasts are often seen in conditions where there is excessive fibrosis, such as in systemic sclerosis, keloids, and hypertrophic scars. They are also found in granulation tissue, which is the pink, vascular tissue that forms during the initial stages of wound healing. The contraction of myofibroblasts helps to close the wound and reorganize the tissue architecture, allowing for the formation of new tissue. This process is mediated by the expression of α-SMA, which is a key marker of myofibroblast differentiation.

**Why Each Wrong Option is Incorrect**
**Option A:** Myofibroblasts are not typically seen in conditions characterized by excessive inflammation, such as in rheumatoid arthritis or acute inflammatory reactions. They are more commonly associated with chronic inflammation and fibrosis.
**Option B:** While fibroblasts do play a role in wound healing, they are not the same as myofibroblasts, which are characterized by their expression of α-SMA and their ability to contract.
**Option C:** Macrophages are a type of immune cell that plays a role in inflammation and tissue repair, but they are not the same as myofibroblasts.

**Clinical Pearl / High-Yield Fact**
Myofibroblasts are often seen in conditions where there is excessive fibrosis, and their contraction helps to close wounds and reorganize tissue architecture. The expression of α-SMA is a key marker of myofibroblast differentiation.

**Correct Answer: D. Granulation tissue.