For a line on a graph to represent an object increasing its speed, the line must show
a) an increasingly steeper slope
b) a negative slope
c) a positive slope that is becoming more horizontal
d) a positive slope

option is A: An increasingly steeper slope

Explanation: Suppose that you are graphing the position of an object with increasing velocity.

in an x vs t graph.

as the velocity increases, the lapse of time needed to travel a fixed distance dx is shorter and shorter, so you will see a positive slope that as the time passes it will become more vertical (never being actually vertical)

Then the correct option is A: An increasingly steeper slope

a skateboard rolling across the street - apex