Can anyone help me in DBMS? I am not able to understand what the question mean?

Asked on January 03, 2015
Question: Consider the following relations for a database that keeps track of student enrollment in courses and the books adapted for each course:
STUDENT(SSN, Name, Major, Bdate)
COURSE (Course#, Cname, Dept)
ENROLL (SSN, Course#, Quarter, Book_ISBN)
TEST (Book_ISBN, Book_Title, Publisher, Author)
Specify the foreign keys for this schema, state if you have any assumption.

Replied on January 03, 2015
ENROLL (SSN) is foreign key of STUDENT(SSN)
ENROLL (Course#) is foreign key of COURSE(Course#)
ENROLL(Book_ISBN) is foreign key of TEST(Book_ISBN)Hope, It will help you.