Please help Which of the following are functions from the set { 1, 2, 3} to the set {a, b, c, d}? If the set of ordered pairs is not a function, explain why not.
a.{( 1,a) , (2, b) , (3, c) , (1, d) }
b.{( 1,a) , (2, b) , (3, a)}
c.{( 1,a) , (2, a) , (3, a)}
d.{( 1,a) , (2, b) , (3, b)}