The correct option is B Potassium
Potasium is an essential mineral needed to regulate water balance, levels of acidity and blood pressure. It is important to controling the activity of heart, muscles and the nervous system. Pottasium works together with the sodium for the nervous system to transmit the messages as well as regulating the contraction of muscles. Pottasium works inside the cell.At about 98% of the potassium in our body can be found in our cell, that is the reason behind that potassium is the most abundant mineral of cellular pool.
so the correct option is 'Potassium'.