**Core Concept**
Anaplasia refers to the loss of cellular differentiation and the presence of primitive or embryonic cell features, often seen in rapidly dividing and aggressive neoplastic cells. This phenomenon is a hallmark of malignant transformation, where normal cellular architecture and function are disrupted.

**Why the Correct Answer is Right**
Anaplasia is characterized by the loss of cellular organization, loss of cell polarity, and an increase in mitotic activity. This leads to the formation of pleomorphic and disorganized cell clusters. In malignant tumors, anaplasia is often associated with the loss of normal cellular adhesion molecules and the disruption of cell-cell and cell-matrix interactions. The presence of anaplasia is a key feature that distinguishes malignant tumors from benign tumors and normal cells.

**Why Each Wrong Option is Incorrect**
**Option A:** Benign tumors are characterized by their slow growth and well-differentiated cellular architecture, which is opposite to the features of anaplasia.
**Option D:** Normal cells exhibit well-organized cellular architecture and differentiation, which is also opposite to the features of anaplasia.
**Option C:** While both benign and malignant tumors can exhibit some degree of cellular disorganization, anaplasia is a hallmark feature specifically of malignant tumors.

**Clinical Pearl / High-Yield Fact**
Anaplasia is often associated with a poor prognosis and is a key feature used in the histopathological diagnosis of malignant tumors. It is essential to recognize anaplasia in tissue samples to distinguish between benign and malignant lesions.

**✓ Correct Answer: B. Malignant tumors**