Twenty students in class A and 20 students in class B were asked how many hours they took to prepare for an exam. The data sets represent their answers. Class A: {2, 5, 7, 6, 4, 3, 8, 7, 4, 5, 7, 6, 3, 5, 4, 2, 4, 6, 3, 5}
Class B: {3, 7, 6, 4, 3, 2, 4, 5, 6, 7, 2, 2, 2, 3, 4, 5, 2, 2, 5, 6}

Which statement is true for the data sets?

A.
The mean study time of students in class B is less than students in class A.
B.
The median study time of students in class B is greater than students in class A.
C.
The range of study time of students in class A is less than students in class B.
D.
The mean study time of students in class A is less than students in class B.