Knowing what you know about the nucleus and the subatomic particles in the nucleus, what do you think is the charge of the nucleus of an atom?

The "charge" of a nucleus is a net positive charge due to the positively-charged protons. Because an atom's nucleus only has protons and neutrons, and neutrons have no charge, there is nothing to cancel out the positive charge of the protons. 

Ithink it is letter b, i may be wrong but i think that is the answer