Step-by-step explanation:
It is known that electron contain a negative charge.
So, when an atom gain electrons then number of electrons within the atom increases. As a result, the atom acquires a negative charge.
Whereas when an atom loses electrons there there will be deficiency of electrons within the atom. As a result, the atom becomes positively charged.
Therefore, when people use plastic combs on their hair, the combs become negatively charged. The situation which is true about this is the comb gains electrons and the hair loses electrons.