Answer:
(B.) a significantly lower mass that protons
Step-by-step explanation:
The mass (in g) of an electron is 9.11 ×
g, which is significantly lower than the mass of protons and neutrons which are approximately the same. They are extremely small (equal to 0 amu), contributing nothing to the overall mass of the atom.
The nucleus has a mass of 1 amu and is positively charged.