单选题 How did diaries such as John Campbell's influence the study?

A、 They demanded more specific classification of visits
B、 They demanded that church attendance be included as visits
C、 They demanded that visiting a friend be classified as intimate
D、 They demanded that both men and women be present.

【正确答案】 A

【答案解析】文章中提到了John Campbell's diary，接着就说研究者创造了以下的定义，即如何定义visit。