Which galaxy is on a collision course with the Milky Way?

The Andromeda Galaxy is the correct answer because it is on a direct collision course with the Milky Way. Current astronomical observations and simulations indicate that the two galaxies are moving towards each other due to their mutual gravitational attraction. In approximately 4.5 billion years, the Andromeda Galaxy is expected to collide with our Milky Way, eventually merging to form a larger galaxy. This event is significant in the study of galactic evolution and the dynamics of our cosmic neighborhood.

The other galaxies mentioned do not share this impending collision trajectory with the Milky Way. While the Whirlpool and Sombrero galaxies are well-known spiral galaxies, they are located at much greater distances and are not on a collision course with us. The Triangulum Galaxy, although it is the third-largest member of our Local Group and does interact with the Milky Way, is not projected to collide with it in the same manner as Andromeda. Thus, the Andromeda Galaxy's trajectory towards the Milky Way is the reason it is the correct answer.