Final answer:
The shoot meristem can differentiate into stems, leaves, or flowers due to its undifferentiated cells that are actively dividing, making B. shoot meristem the correct answer.
Step-by-step explanation:
The region of a plant that can differentiate into stems, leaves, or flowers is known as the shoot meristem. This embryonic area has two primary characteristics: the cells are dividing to produce more cells, and they are small, undifferentiated, and not yet committed to a final cell type. The shoot apical meristem is part of the shoot meristem and is responsible for the primary growth of the plant, producing new shoot material as well as leaves. The activity of these meristems is crucial for the elongation of the shoot and the formation of other structures, such as leaves and flowers. As such, the correct answer to the student's question is B. shoot meristem.