Answer:
A. The car travels the same distance per unit of time because the portion shows a linear, increasing function.
Step-by-step explanation:
The portion of the graph labelled I is linear increasing function. So, the slope is constant. The slope is the the ratio of change in the quantity of y-axis to that of x-axis.
Here distance is plotted in the y-axis and time in the x-axis.
So, the slope here is Distance covered/ Time, which is nothing but the speed of the car.
Since the slope is constant, the car is travelling at a constant speed in the portion of the graph labelled I, which means, the car travels the same distance per unit of time in the portion I.