Resting membrane A. Hormones

B. Neurotransmitters

C. Ion pump

D. None of the above

Ion Pump

Explanation:

Resting membrane potential is maintained by ion pump which transports outward and inside the cell.

Neurotransmitter transmits signals across a chemical synapse from one neuron to another neuron.

Hormones are chemical substances secreted by endocrine glands directly into bloodstream. They act as messengers and control and coordinated activities of the body.