Samaj is making cupcakes for the school fair. One box of cake mix will make 20 cupcakes. Two boxes of cake mix will make 40 cupcakes. The constant of proportionality is k = 20. Which statement explains the meaning of the constant aof proportionality?

A) There are 20 cupcakes in one box of cake mix.
B) There is one cupcake in 20 boxes of cake mix.
C) There are 40 cupcakes in one box of cake mix.
D) Samaj does not have enough cake mixes to make the cupcakes needed.