## Explanation

### Analysis of Statements about Acceleration

Let's evaluate the given statements to determine their validity.

### Statement (a): A car must always have an acceleration in the same direction as its velocity

This statement is **incorrect**. A car can have an acceleration in a direction opposite to its velocity, which typically leads to a decrease in its speed (deceleration). For example, when a car is moving forward but the driver applies the brakes, the acceleration is directed opposite to the direction of the car's velocity.

### Statement (b): It's possible for a slowing car to have a positive acceleration

This statement is **true** depending on the chosen frame of reference. In physics, acceleration is a vector quantity that depends on the coordinate system. If we consider a positive acceleration to be in the opposite direction of the velocity (assuming we are moving in the negative direction), the car will slow down.

In this case, the car has a negative velocity (moving backward) but a positive acceleration, causing it to slow down in the backward direction.

### Statement (c): An object with constant nonzero acceleration can never stop and remain at rest

This statement is **true**. If an object has a constant nonzero acceleration, this implies that it is continually changing its velocity. Therefore, it cannot stop and remain at rest because remaining at rest would mean having zero velocity and zero acceleration.

**Important note**: The constant acceleration ensures that the object transitions through various velocity states without pausing.

Given these evaluations, we conclude that statement (b) and **statement (c) are true**, while statement (a) is false.