The range of a relation is given - 2,-1,0,1,2 which domain would make the realation not a function

Any domain that has at least one (1) of the inputs (domain values) having more than one output (range values). For example, a domain of {1, 2, 3} because since there are 5 outputs and only 3 inputs, at least one input would have to pair up with more than 1 output.