If someone could help with this question
Ok, so from the body of the question we know MG is an autoimmune disease and involves antibodies. This doesn't help us narrow down the options so much so we take a look at the diagram.
We see in healthy individuals, acetylcholine (red dot) is released from the nerve cells. It binds to the purple receptor on muscle cells. This transfers the signal from cell to cell and at the NMJ will result in the contraction in the muscle cell.
In the disease example, we can see the antibodies that are part of the MG disease binding the purple receptor. What does this mean for the acetylcholine that is being released by the nerve cell/motor neuron?
Using this info, you should be able to piece together what is happening to cause symptoms.
To start you off, we can easily get rid of option A as the antibodies are not targeting the motor neurons.