a machine can make 56 parts in 4 hours. it can also make 70 parts in 5 hours. which rates could you use to write an equation of the form y= kx that represents the number of parts y the machine can make in x hours? A. 70 parts / 4 hours B. 70 parts / 5 hours C. 56 parts / 4 hours D. 56 parts / 5 hours​