There are 54 people playing tennis at the regional event at the same time. Some are playing doubles, and some are playing singles. There are 18 matches in progress. A singles match requires 2 players, and a doubles match requires 4 players. This can be modeled with this system of equations. 2s + 4d = 54 s + d = 18 Which ordered pair is the most reasonable solution to this system of equations?

(9, -9)


(-9, -9)


(-9, 9)


(9, 9)