d. Nervous tissue
The nervous tissue is composed of nerve cells or neurons that are responsible for communications thru involuntary and voluntary movements.
The neuron, a cell that composes the nervous system. For example a brain, an organ composed of thousands of neural fibers and glial cells that performs many important organismic functions.
Neurons are specialised cells that have dendrites, axons and terminal buttons that sends and receives stimuli from the environment and transduces it into a meaningful information and understand the complexities which the brain now functions.