1. Which of the following sets of ordered pairs defines a relation?
A. {(3,2).(-3,6).(3,-2).(-3,-6)}
B. {(1,2), (2,6). (3,-2), (4,-6)}
none D. all of the above
C. {(2,2), (2,3), (2,4), (2, -9)}
D.all of theabove​