true or false?

Question

5.:Let f: X →Y be a function.True or False?A sufficient condition for f to be one-to-one is that for all elements y in Ym there is at most one x in X with f(x)= y.

Answer 1

False, because the definition of being one to one or an injection is for all x and y in the domain of the function such that

f (x)= f (y) implies that x=y.