C
1) Examining those Dot Plots we can gather the following information:
Grade 6
minutes | student(s)
5 1
10 2
15 5
20 4
25 2
30 3
35 3
Grade 7
minutes | student(s)
5 0
10 1
15 2
20 4
25 3
30 5
35 5
2) Examining the options, we have the correct answer.
C) Grade 6 15minutes to 25 minutes: 11 students
Grade 7 15min to 25 min: 9 minutes
3) Hence, the answer is C