Which neurotransmitter is released by motor neurons at the neuromuscular junction?

Acetylcholine

Explanation:

Myoneural junction or neuromuscular junction is the chemical synapse formed where the motor neuron connects with the muscle fibres.

The neuromuscular junction plays an important role in muscle contraction as the electrical impulse from the brain gets transferred to the muscle fibre.

Since the junction is a chemical synapse, therefore, the electrical signal gets converted into the chemical signal therefore neurotransmitter is released at the junction which is the acetylcholine. Acetylcholine binds to the receptor and the signal is transferred.

Thus, Acetylcholine is the correct answer.