Which of the following sets represent invertible functions? Select all that apply. 1{(2,3), ( - 2,5), (2,6),(4,6), (5,2)}
2{(2,3).(-2,5), (3, 6), (4,8), (5,2)}
3{(2,3).(-2,5), (-3,6).(-4,7), (5, 4)}
4{(2,3), ( - 2,5), (3, 6), (4, 6), (5, 2)}