Choice C is the one that makes sense, because a positive relationship happens when the independent variable increases and the dependent variable also increases.
In this case, the speed is the dependent variable and the distance is the independent variable.
On the other hand, it doesn't make sense that as the speed decreases, the distance increases, because the distance and the speed are directly proportional, that is, if one increases the other one also increases.
So, this directly proportional relationship is described choice C, which is a positive relationship, because as the speed increases, the distance also increases.
A scatter plot for speed and distance is created.
We know that distance = speed x time
Hence when speed increases, distance increases and similarly when speed decreases, distance decreases.
Thus if we plot on x axis speed and y axis distance, we find that x increases when y increases.
So we find that there is a strong positive relationship between the two variables
where D = distance S= speed and t = time.
Since D varies directly as speed, we have positive relationship.