How Many Protons, Neutrons, and Electrons Are in the Ion

How many protons, neutrons, and electrons are in the ion, ³⁷Cl^-?

A) 37 protons, 18 neutrons, and 37 electrons
B) 18 protons, 37 neutrons, and 17 electrons
C) 17 protons, 20 neutrons, and 18 electrons
D) 37 protons, 20 neutrons, and 18 electrons
E) 17 protons, 17 neutrons, and 37 electrons