Which of the Following Is a Requirement for a State's

Which of the following is a requirement for a state's school aid to a parochial school to be deemed constitutional?

A) The purpose of the financial aid must be clearly secular.
B) The primary effect of the aid must inhibit religion.
C) The aid must demonstrate the active involvement of the sovereign in religious activity.
D) The aid must be solely used to fund the salaries of teachers of secular courses.
E) The aid must be used for textbooks and instructional materials of certain secular subjects.