Astudent proposes this hypothesis in class: "if i make the angle of a ramp steeper, then a ball rolling down the ramp will be going faster when it hits the ground.”

which part of a hypothesis should the student add to this that could also be tested in other experiments?

a: an explanation based on prior scientific knowledge or observations
b: an explanation of how the hypothesis will inspire new questions
c: an independent variable that the student controls during the experiment
d: an independent variable that is affected by the other experimental variable