Explanation:

- Ascent: This word means the act of rising or climbing up. It often refers to an upward movement or progression.

- Option 1: Distant: This word typically means far away or remote. It doesn’t relate directly to movement or direction, so it's not an antonym for ascent.

- Option 2: Depression: Generally refers to a low mood or a low point, but not specifically in the sense of moving downward. Therefore, it's not a suitable antonym for ascent in the context of physical movement.

- Option 3: Descent: This is the opposite of ascent. It means moving downwards, the act of declining or decreasing. It’s directly related to the idea of movement, making it the correct antonym.

- Option 4: Decent: This word refers to being satisfactory or adequate. It doesn't describe a direction or movement, thus not an antonym for ascent.