Which best describes the nucleus of an atom?
a. it contains no mass.
b. it is the negatively charged part of the atom
c. it is made of neutrons and electrons.
d. it is the most massive part of the atom.

D. It is the most massive part of the atom.

Explanation:

As you know, an atom is formed by the electrosphere (where the electrons are) and the nucleus (where the neutrons and protons are).

The nucleus is a very small region in the atom and although it occupies less space than the electrosphere, it contains practically the entire atomic mass, for this reason it is the densest region of the atom. This is because the entire mass of an atom corresponds to the sum of all its protons and the protons are in the nucleus.

i don't know. if i were you, i would search it up online : d

i believe your answer would be c.. : )