The answer is C. All students enrolled at Springfield high school.

so
(this is wrong because
)
this is what i got when i divide 1. 66666666667 i am not sure please tell me if wrong for me to go over it with my tauter
A = 1/2 bh
A = 1/2 (21)(8)
A = 1/2 (168)
A = 84