Which of these graphs best illustrates
how the velocity of the free-falling rock
changes during the first four seconds?

Each graph shows Velocity and time with the first graph showing a line drawn from the left bottom corner straight up at an angle going up to the right top corner of the graph.

The second graph shows a curved line from the left corner at the bottom of the graph, rounding upwards to the corner of the graph at the right top corner.

The third graph shows a straight line going from the top left corner straight to the bottom right corner.

The fourth graph shows a curved line going from the left corner at the bottom, curving up and down to the right corner on the bottom right side corner.