Final answer:
Our galaxy, the Milky Way, has a diameter of approximately 100,000 light-years, indicating that option c (130,000 light-years across) most accurately represents the scale of our galaxy.
Step-by-step explanation:
The question pertains to the scale of our galaxy, the Milky Way, and its actual diameter. From the provided information, the Milky Way's visible disk is measured to be about 100,000 light-years across. This is substantial in comparison to the distances to other galaxies such as the Andromeda Galaxy, which is approximately 2.4 million light-years away. It's important to note that although individual galaxies like the described Andromeda galaxy appear separate, they are all part of a greater universe that is filled with countless stars and planets.