Which of the following sets of ordered pairs (x,y) is NOT a function of x?

Responses

{(0,1),(1,0),(1,1)}

{ ( 0 , 1 ) , ( 1 , 0 ) , ( 1 , 1 ) }

{(0,0),(1,1),(2,2)}

{ ( 0 , 0 ) , ( 1 , 1 ) , ( 2 , 2 ) }

{(0,0),(1,1),(2,1)}

{ ( 0 , 0 ) , ( 1 , 1 ) , ( 2 , 1 ) }

{(0,1),(1,1),(2,1)}

{ ( 0 , 1 ) , ( 1 , 1 ) , ( 2 , 1 ) }