Which Describes the Basic Concept of Bohr's Theory of the Atom

Which describes the basic concept of Bohr's theory of the atom?

A) Atoms contain a small,dense positively charged region called the nucleus.
B) The energy of an electron in an atom is quantized; it has only certain allowable values.
C) Light is made up of particles called photons.
D) Electrons have the magnetic property of spin.
E) Radioactive atoms spontaneously decay and release large amounts of energy from the nucleus.