How is the Bohr atomic model different from the plum-pudding model? A. In Bohr's model, the atom's mass is found at its center instead of
distributed throughout.
B. In Bohr's model, the atom's mass is mostly made up of electrons
instead of protons.
C. In Bohr's model, the volume of the atom is mostly made up of the
nucleus.
D. In Bohr's model, the atom consists of positive charges circling a
negatively charged nucleus.

A. In Bohr's model, the atom's mass is found at its center instead of distributed throughout.

Explanation:

The Plum-Pudding model of an atom was  proposed by the late J.J Thompson. In this model, an atom is seen as negative charged particles that are surrounded by a soup of positive charge, which was liken to Plum Pudding, an English dessert.

While in Bohr's model of an atom; negatively charged electrons move in clearly defined circular orbits around the atom's mass (positively charged), called Nucleus.