What is the value of C.O.P. in the following diagram?

• A. 210 Q / m1 (h2 – h4) + m2 (h5 – h6)
• B. 210 Q / m1 (h2 – h7) + m2 (h6 – h8)
• C. 210 Q / m1 (h2 – h8) + m2 (h5 – h8)
• D. 210 Q / m1 (h2 – h1) + m2 (h6 – h5)