Answer:
Letter B - Electrolytes.
Step-by-step explanation:
Nerve signal conduction and muscle contraction depend on electrolyte balance to occur.
Sodium, potassium, and chlorine, for example, are typical electrolytes found in the body that are present in the nerve impulse due to the process of cellular depolarization.
Basically, for the conduction of the nerve signal to happen, it must happen the depolarization of nerve cells that control muscle contraction and in this process, there is mainly sodium and potassium change, while for actin-myosin system activation and finally muscle contraction, We mainly need calcium.
So, in general, an electrolyte balance is required during both processes.