Which relation is a function? A {(2,-3), (2,-2).(2.-1).(2.0), (2.1)} B {(8.-2). (9.-2).(10,- 2).(11.-2).(12,3)} с c. {(9,3). (9,-3). (16,4). (16.-4). (25.-5)} {(1, 1), (2, 4). (4,8). ( 8.16). (8,32)}