The Ridgeport school district collected data about class size in the district. The table shows the class sizes for five randomly selected kindergarten and seventh-grade classes.
Number of students in randomly selected class Mean Mean absolute deviation
Kindergarten 17, 18, 19, 21, 20 19 1.2
Seventh grade 25, 30, 27, 29, 34 29 2.4
Based on these data, which statement is true?

A.
The recommended number of students in a kindergarten class is 19.
B.
The average size of a seventh-grade class is larger and varies more than that of a kindergarten class.
C.
The average size of a seventh-grade class is larger but varies less than that of a kindergarten class.
D.
Every seventh-grade class has 10 more students than a kindergarten class.