Question

quesiong in coments

Answer 1

In order for a relation to be a function it must have no repeating x-values, but it can have repeating y-values

Answer 2

you can use the line test to find our if a function is a relation

Answer 3

for example, draw a line through all coordinates (going vertically) and if 2 or more points match up then it is not a relation

Answer 4

so it's D then ? ( sorry for late response )