Is the Mass of an Atomic Nucleus Greater or Less

Multiple Choice

Is the mass of an atomic nucleus greater or less than the sum of the masses of the nucleons composing it? Why don't the nucleon masses add up to the total nuclear mass?

A) Greater.We need to add the masses of the surrounding electrons to the masses of the nucleons.
B) Neither.The mass of the atomic nucleus is exactly the sum of the masses of the nucleons.
C) Less.The individual nucleons have greater mass when separated from the nucleus.This additional mass is a result of the energy of separation.
D) Greater.The mass of the atomic nucleus also has mass of the "atomic glue" that holds the nucleons together in the nucleus.