a b c d

a

$f:\{1,2,3....\}→\{1,4,9....\}$ $f(x)=x^2$ → codomain = range for every x there exists atleast one x → it is onto $f(x_1)=f(x_2)⇒x_1=x_2$   (one-one) The correct answer is option (1) - Bijective