An issue the students encountered is that the marble doesn't land on the launch pad all of the time. To remedy this, they consider constructing a funnel to help direct the marble. How do you suggest the students move forward with their design process in order to find a solution?
A Test funnels of the same size and material with varying sized openings.
B Test funnels of the same shape and size with varying materials.
C Test funnels with identical openings and material with varying size.
D Test all of the above funnels and then construct a funnel with the best design elements from each.​