Mrs. Bergstedt teaches six classes. In her first period class she has 19 students, her third period she has 13 students, her fourth period 19 students, her fifth period 9 students, her sixth period 14 students, and her seventh period 15 students. What is her average class size, to the nearest tenth?
A) 14 students
B) 14.8 students
C) 17 students
D) 17.8 students