Let f : N $\to$ Y be a function defined as $f(x) = 4x + 3f(x)=4x+3$ where $Y = \{ y \in N ; y = 4x + 3Y=\{ y \in N; y= 4x+3$ for some $ x \in N \}x \in N \}$. If 'f' is invertible.

Question

$(A)\;Invertible$
$(B)\;Non - invertible$
$(C)\;Cannot\; be\; determined$