Answer:
The correct answer will be option-A
Step-by-step explanation:
A skeletal muscle comes into action when it receives a signal from the Central nervous system in the form of the action potential.
The action potential triggers the release of the neurotransmitter called Acetylcholine which causes depolarization in the motor endplate. The depolarized signal is transferred from the motor endplate to sarcolemma through T-tubules which innervate the muscle cells.
The action potential then triggers the release of the calcium ions from the sarcoplasmic reticulum to sarcoplasm of the muscle cell. This activates troponin which causes the muscle cell to move.
Thus, option-A is the correct answer.