Which of the following is a function, Please i need this its due in 15 min
A= {(1, 4) (2, 5) (3, 6) (4, 7)}
B={(-3, 4) (-1, 6) (2, 4) (5, 5)}
C={(-1, 2) (3, 5) (-1, 4) (7, 12)}
D={(1, 5) (4, 5) (5, 5) (8, 5)}