Velocity is the derivative of position. If the velocity is positive, the slope is positive. Here you should cross out D and E.
Acceleration is the derivative of velocity. If acceleration is positive, think of it as "the rate of change of the velocity is positive"...that is....the velocity is increasing. A doesn't show any increase in velocity. Cross it out.
The answer is C since it is increasing...it will not just reach a random limit and stop.