Answer: option C, elementary school and post-secondary school.
Explanation: The options were in a comment that you provided:
A.middle school and high school.
B.post-secondary school and higher education.
C.elementary school and post-secondary school.
D.kindergarten and elementary school.
Elementary school (as the name says) is the elementary knowledge needed for everyone, this comes before.
Middle school is equivalent to secondary school, and high school is the last school previous to the university.
The answer here is option C.
Secondary school comes after elementary school, and before that postsecondary school (post means that comes "after" something).