The word "prevalent"(Sentence 1, Para. 1)in this passage means

A．compel the subjects to separate major information from minor details
B．put the subjects through increasingly complex tests
C．cheek the effectiveness of nicotine on smokers
D．register the prompt responses of the subjects

A．Each community differed in the method of controlling the schools.
B．The salary of the teacher was determined by the local authority.
C．The supervising committee of the school was often composed of church people and some important figures of the town.
D．All communities carried the same principle in organizing these schools.