Answer:
a. At the bottom of the first dip in the track when the car is moving the fastest.
Step-by-step explanation:
P.S - The exact question is -
The correct option is - a. At the bottom of the first dip in the track when the car is moving the fastest.
Reason -
From the diagram , we can see that the total mechanical energy of the roller coaster car is greatest At the bottom of the first dip in the track when the car is moving the fastest.