Explanation:

- The area under the velocity-time graph represents the change in displacement.

- This is because if you integrate velocity with respect to time, you get displacement.

- Option 1: Its average velocity - This is not determined by area; it's the total displacement divided by total time.

- Option 2: Its net displacement - This is correct. The area under the velocity-time graph gives the net displacement.

- Option 3: The distance travelled by it - For distance, you need the total area considering velocity's magnitude (absolute value).

- Option 4: Its average speed - This is total distance divided by time, not directly given by graph area.