China Naming Network - Ziwei Dou Shu - One grade 14 class, each class has 50 students, and the random number is 1 ~ 50. In order to understand their interest in extracurricular activities, the 40th student in each class is required.

One grade 14 class, each class has 50 students, and the random number is 1 ~ 50. In order to understand their interest in extracurricular activities, the 40th student in each class is required.

D

Because each class uses the same student number and the same spacing, it is a systematic sampling method.