Final answer:
The true statement is that a person slowing down and traveling in the negative direction is producing a positive acceleration, as positive acceleration acts in the opposite direction of the negative motion causing it to slow down.
Step-by-step explanation:
The correct statement among the options provided is: c. A person slowing down and traveling in the negative direction is producing a positive acceleration. When an object or person is moving in the negative direction (to the left in a standard coordinate system) and is slowing down, it means that the acceleration is acting in the opposite direction to the motion, which is towards the right or in the positive direction. This concept is shown in the reference, where an object moving with a large negative velocity slows down to a velocity less negative, indicating a positive change in velocity, and thus positive acceleration.