If cot θ (1 + sin θ) = 4m and cot θ (1 – sin θ) = 4n, then which one of the following is correct?

• A. (m2 + n2)2 = mn
• B. (m2 – n2)2 = mn
• C. (m2 – n2)2 = m2n2
• D. (m2 + n2)2 = m2n2