b, short explanation remember the sets are set up like (x,y) in a set there should be no matching x points so if it matches it's not a function :)
long explanation: these are (x,y) sets {(0,3), (3,0), (0,4), (4,0)} the first choice shows that there are two X solutions if they are equal to 0 (0,3) (0,4) so this cant be a function.
second choice {(0,2), (2,0), (4,6), (6,4)} does not have two X solutions so this is a function
third choice{(2,6), (3,6), (4,6), (2,0)} has two X solutions if x is equal to 2
and the last choice {(6,2), (2,0), (4,6), (6,4)} has two X solutions if x is equal to 6
hope i helped! if i did please give me brainlest :)
