Question

Which relation is a function?

A {(1, 2); (2, 3); (3, 4); (4, 5)}
B {(1, 2); (1, 3); (1, 4); (1, 5)}
C {(1, 2); (2, 3); (3, 4); (2, 5)}
D {(1, 2); (3, 2); (3, 3); (4, 2)}

Answer 1

a relation will have NO X-REPEATS

so the one that doesn't have any X-REPEATS is a function

Answer 2

which one doesnt have any \[ X-repeats\]