The eighth grade is taking two buses for the class field trip to the science museum. Each bus seats exactly 30 passengers. There are 3 eighth-grade classes, one with 26 students, one with 18, and one with 20. There are 3 teachers going on the trip. Will they need to order another bus?
A. No, there are 3 empty seats left over after filling the buses.
B No, the buses are filled exactly to capacity.
C. Yes, the buses are short 6 seats.
D. Yes, the buses are short 7 seats.​