At a restaurant, hot chocolate can be purchased in two different cup sizes. A 12-ounce cup costs $3.60 and a 16-ounce cup costs $4.80.

Is the linear relationship between cup size and cost also proportional? Why or why not?

Yes, the constant of proportionality is 0.3.
Yes, there is no constant of proportionality.
No, the constant of proportionality is 0.3.
No, there is no constant of proportionality.