If m cot A = n, then the value of\(\dfrac{m.Sin~A - n.Cos~A}{n.Cos~A + m.Sin~A}\) is

• A. \(\dfrac{n^2 + m^2}{n - m}\)
• B. \(\dfrac{m^2 - n^2}{n^2 - m^2}\)
• C. \(\dfrac{m^2 - n^2}{m^2 + n^2}\)
• D. \(m + \dfrac{n^2}{m^2}\)