Answer: Function
Quick explanation: The x coordinates do not repeat, so we have a function.
Longer explanation:
A function is possible if and only if each x input leads to exactly one y output value. Something like x = 6 leads to y = 0 and nothing else. If we had say (6,0) and (6,5) then we won't have a function. But as mentioned above, the fact x doesn't repeat itself means we do have a function.
To visually check, plot the points on the xy grid. Notice it is impossible to draw a single vertical line through more than one point. Therefore, the relation passes the vertical line test and visually confirms we have a function.