Hello, and thanks for posting your question!
A function would be a set of ordered pairs that have no repeating "x" values, look at the example below. (V)
{(1, 0), (2, 0), (3, 0)} = Function
{(1, 0), (1, 0), (2, 0)} = Not a function.
According to this information, your answer is C. Both Set A and Set B.
Hope this helps! ☺♥