When normal cells become malignant it is known as:

A) differentiation.
B) encapsulated.
C) dedifferentiation.
D) neoplasm.

When normal cells become malignant, they undergo dedifferentiation, which means they lose their specialized features and become more primitive in their appearance and function. This is a hallmark feature of cancer cells. Option A (differentiation) refers to the process by which cells become specialized during embryonic development. Option B (encapsulated) refers to a tumor that is confined to a specific area and surrounded by a fibrous capsule. Option D (neoplasm) refers to an abnormal growth of cells that can be either benign or malignant.