Which of the following could be the equation of the line of best fit?

The scatterplot above shows the speeds of different runners over time.

Which of the following could be the equation of the line of best fit?
A . S = C2 × (t C 15)
B . S = Ct + 25
C . S = C1/2 × (t C 10)
D . S = C1/2 × (t C 20)
E . S = 2 × (t + 15)

Answer: A

Explanation:

If a straight line were drawn through as many of the plotted points as possible, it would have a negative slope. The line slopes more sharply than the line y = Cx × (a line with a slope of C1), so the line would have a slope more negative than C1. The line would also have a y-intercept well above the x-axis. The only equation given with a slope more negative than C1 is S = C2 × (t C 15).