Consider the relation schema {program, course, professor, student, score} and the following FDs: (We use "to" for the arrow.)

course,student to score

course to professor

professor to program

Which of the following statements are correct?

	1.	the closure of {professor} is {professor, program, course}
	2.	the closure of {course, student} is {course, student, score}
	3.	{program} is a key
	4.	{course, professor} is a key
	5.	{course, student} is a key
	6.	This is in BCNF.
	7.	{student, score} is a key