A group of students is investigating whether wheels affect the force of friction. The students push two boxes each with the same force on a table. One box has wheels and the other does not have wheels. The distance traveled by each box is shown. Experimental Observations
Student 1 Student 2 Student 3 Student 4

Distance traveled by box with wheels 24 cm 22 cm 20 cm 23 cm
Distance traveled by box without wheels 12 cm 14 cm 15 cm 13 cm
Which step should the students take next? (3 points)

a
Make a hypothesis

b
Test another variable

c
Analyze the results

d
Share their conclusion