Which relation is not a function?
A
{(10,-5), (8,-4),(4, -2),(2,0)}
B
{(1, -2), (1,-4), (1.0), (1,8)
C С
{(-3,9),(-2,4),(-1.1), (1,1)
D
{(3,10),(5, -5), (6,6), (9,11)}