Assertion : Plotting the acceleration-time graph from a given...

Assertion is correct: From a position-time graph, you can find the velocity (slope). From the velocity-time graph (derived from position-time), you can find the acceleration (slope). So, indirectly, it is possible. Reason is correct: The concavity of the position-time graph gives information about the sign of acceleration. A concave up curve indicates positive acceleration, and a concave down curve indicates negative acceleration. The reason provides a correct statement about position-time graphs and acceleration, but it doesn't fully explain how plotting an acceleration-time graph is possible from a position-time graph (which involves two steps: position to velocity, then velocity to acceleration).