It would change the charge, a neutral atom has zero charge but a proton has a positive charge. So 0 charge + 1 positive charge = 1 positive charge.
The equation is pv=nrt. So to decrease pressure, one would increase volume, decrease moles, or decrease temperature.
C. Electron. It’s a negatively charged particle that orbits around the nucleus. Usually, there are multiple electrons going around the nucleus in different orbitals (the circle around the nucleus in which the electron travels). The mass is much smaller compared to that of a proton or neutron and can be ignored when calculating the mass of an atom.
