Question

Which relation describes a function? What makes it a function?
A)
{(-2,3),(-3,3),(-4,3)}- Each member of the domain is assigned exactly one member of the range.
B)
{{2,3),(2,-4),(2,5)}-Each member of the range is assigned exactly one member of the domain.
C)
{(-2,3),(-4,5),(-6,7)}- Each member of the domain and range is unique.
D)
{(2,3),(3,3),(3,4)}=Each member of the domain and range is positive.