Smoothies cost $3 for small drinks and $7 for jumbo drinks. Ethan creates two patterns to compare the costs. He writes ordered pairs in the form (small drink, jumbo drink) for the corresponding numbers of drinks. Which ordered pairs could be on Ethan's list?
A. (6,10)
B. (9,21)
C. (12,24)
D. (15,35)
E. (42,18)