Let $f : N\rightarrow Y$ be a function defined as $f (x) = 4x + 3$, where $Y = {y\; \epsilon \;N : y = 4x + 3 for \;some\; x \;\epsilon\; N}$. Show that f is invertible and its inverse is

Question

( A ) $g(y)=\frac{3y+4}{3}$
( B ) $g(y)=\frac{y-3}{4}$
( C ) $g(y)=4+\frac{y+3}{4}$
( D ) $g(y)=\frac{y+3}{4}$