Answer:
The answer is c) 1e-
Explanation:
The chemical change is the loss of 1 electron (1 e-) in 1 atom of sodium (Na) to give a sodium cation (Na⁺). You have to put the electron in the cation side of the equation. In this way, the overall process is electrically neutral (1 positive charge is neutralized by 1 negative charge and the other side has not charges):
Na → Na⁺ + 1 e-