Explanation:

- The relationship between the words "Snake" and "Slithering" is based on how a snake moves.

- Therefore, the task is to find a word describing how a horse moves.

Options:

1. Galloping

- This describes a fast gait of a horse.

2. Strolling

- Refers to walking in a leisurely way, not specific to horses.

3. Hiking

- This generally pertains to walking outdoors on trails, not specific to animal movement.

4. Grooming

- Refers to cleaning or maintaining appearance, not related to movement.

Thus, "Galloping" is the correct answer, as it describes a typical movement of a horse.