C
Below is a question with multiple-choice answers. Choose the correct option based on your reasoning.

### Question:
The Milky Way is a part of 30 or more galaxies called the Local Group. Which would be the most likely reason these galaxies are considered to be part of the Local Group?

### Choices:
A. They are all the same type of galaxy.
B. They all have the same number of stars.
C. They are all attracted to each other by gravity.
D. They can all be seen without the aid of a telescope.

### Answer:
