Final answer:
The three main components of a spiral galaxy are the bulge, disk, and halo. These structures encompass older and younger stars, interstellar matter, and spiral arms where new stars are formed.
Step-by-step explanation:
The three main components of a spiral galaxy are: bulge, disk, and halo. Spiral galaxies like the Milky Way and the Andromeda galaxy are characterized by these components. The central bulge is typically comprised of older stars and may contain a supermassive black hole at its core. The disk of the galaxy is composed of dust, gas, and both young and old stars. It contains the spiral arms that wind out from the center of the galaxy, where new star formation often occurs. The halo is a spherical, outer region of the galaxy, which contains older stars and is thought to also contain a significant portion of the galaxy's dark matter.
Answer: b) Bulge, Disk, and Halo