This question asks us to compare the heights of two balls at a specific time:
t=0.9
The graph shows:
Ball 1 as the solid blue curve.
Ball 2 as the dashed blue curve.
To determine which ball was lower at t=0.9, we look at the vertical positions of both curves when the time is
0.9seconds.
At approximately t=0.9:
" height of Ball 1 " < " height of Ball 2 "
This means Ball 1 is lower than Ball 2 at that time.
The correct reasoning must say both:
Ball 1 was lower, and
Ball 1's height was less than Ball 2's height at t=0.9.
That matches option A.