________ in the regulations that you should not tell other people the password of your e-mail account．
A.What is requiredB.What requiresC.It is requiredD.It requires在线课程C
解析：
句意为“规定要求你不能告诉别人你的电子邮箱的密码”。此处构成“It is+过去分词+that-clause”句型，其中it为形主语，that从句为真正主语，谓语动词须用被动语态。what不能作形主语，若选A项，题干可改写为What is required in the regulations is that…，这样what从句为主语从句，that从句作表语从句。