If the function \(f: \mathbb{N} \to \mathbb{N}\) is defined as \(f(n) = n - 1\) if \(n\) is even, and \(f(n) = n + 1\) if \(n\) is odd, then (A) f is injective (B) \(f\) is into (C) \(f\) is surjective (D) f is invertible Choose the correct answer from the options given below :