The dotplot below displays the number of math classes taken by a random sample of 35 students at a high school.
A dotplot titled Math Classes. A number line going from 2 to 6 is labeled number of math classes taken. 2, 1; 3, 6; 4, 18; 5, 7; 6, 1.
Which letter represents the approximate location of the mean number of math classes?
A. A
B. B
C. C
D. D