The slope of a speed-time graph indicates

a. acceleration.

b. speed.

c. direction.

d. velocity.

A. Accelleration

A graphs slope has the formular rise/run, in this case, the change in speed/change in time (because speed is on the y-axis which means it is the "rise" and time is on the x-axis which means it is the "run").

If you go to a formulae sheet, you will see that a = change in speed/change in time.

This is the same as the formular of the graph therefore the slope of a speed-time graph indicates accelleration