If y = f : A → B, then which of the following is true if f(x) is a function in x?
(i) x must be able to take each and every value of A.
(ii) one value of x must be related to one and only one value of y in set B.
Both (i) and (ii)
Both (i) and (ii) are part of the definition of function. ((i) and (ii) together forms the definition of function).