Which of the relations given by the following sets of ordered pairs is not a function? C {(5, 1), (4, 1), (3, 1), (2, 1), (1, 1)}
C {( – 5, – 7), ( – 4, – 6), ( – 3, – 5), ( – 2, – 4), ( – 1, – 3)}
C{( – 4, – 2), ( – 1, – 1), (1, 3), (1, 4), (7, 10)}
C{( - 4, – 4), ( – 3, – 3), (0,0), (3, – 3), (4, – 4)}