A test vehicle travels at a constant speed v v\,v along a horizontal track shaped like a figure-of-eight, as shown below. The vehicle starts at point PPP, completes exactly one full circuit of the track, and returns to point P P\,P after a total time interval TTT.

Which statement correctly describes the vehicle's motion during this time interval TTT?
The average velocity over the interval TTT is 000, but its instantaneous velocity is changing.
The average velocity over the interval TTT is vvv, and its instantaneous velocity is constant.
The average velocity over the interval TTT is vvv, but its instantaneous velocity is changing.
The average velocity over the interval TTT is 000, and its instantaneous velocity is constant.