Question

[Choose the one correct answer and explain your reasoning.]

Let \(N=2^k\times4^m\times8^n\)where \(k,m,n\) are positive whole numbers. Then \(N\) will definitely be a square number whenever

  1. \(k\) is even;

  2. \(k+n\) is odd;

  3. \(k\) is odd but \(m+n\) is even;

  4. \(k+n\) is even.