It is in the air 5.625 seconds.
Using the quadratic formula,

0 is when the ball is first launched, 5.625 is when it hits the ground again.
Y-y1= m(x1-x2)
using this formula
the answer is d
because slope has to remain the same if its parallel
If the hypothesis was wrong, all you simply have to do is state the hypothesis was wrong and why you think it was, and add what you can do to change it or to make it better so next time it will be right. Just state what you did and how you got your answer.
I hope that helps!