A car with a leftward velocity and a rightward acceleration is

A moving left and speeding up

B moving left and slowing down

C moving to the right and speeding up

D moving to the right and slowing down

E Two or more of the above are possible

A car with leftward velocity and a rightward acceleration will move left and slowing down. Because whenever a car moves in a specific direction, then by applying an opposite acceleration or brakes won’t make its direction spontaneously in the direction of applied brakes or acceleration, but it will first slow down the car, and then make it stop due to applied brakes and then moves it in the direction of applied acceleration.

So option "B" is correct.