what volume of a 12.1 M HCl stock solution is required to make 1.25L of a 3.0 M hydrochloric acid solution

In chemistry, the type of an atom (what element it is) is determined by: a) the number of protons it contains in its nucleus.b) the number of neutrons it contains in its nucleus.c) the number of protons it has in a cloud around the nucleus.d) the number of neutrons it has in a cloud around the nucleus.e) the number of electrons it exchanges with its neighbors.