Choices 'B'; and 'D' both begin with the correct words.
But they should end with the equation
R = V / I
I believe it is acceleration
A. The cliff was 30.7 m high
B. I also got 9.5 as the horizontal distance
Here is my work, I find making charts like this one to find knowns and unknowns can be helpful
Letter D: The amount of sleep a student gets affects student achievement