Final Answer :
The body's longest cells are neurons, making option D) Neurons the correct answer.
Explanation:
Neurons are specialized cells of the nervous system responsible for transmitting electrical impulses over long distances. Their unique structure includes a long axon, the nerve fiber, which can extend for considerable lengths, allowing for communication between different parts of the body.
This structural adaptation enables neurons to transmit signals efficiently over extended distances, facilitating the complex network of communication within the nervous system.
While muscle cells (option C) can also be elongated, neurons are specifically designed for rapid and long-range transmission of information, making them the longest cells in the human body. The correct option is D.