If we add, 7xy + 5yz – 3zx, 4yz + 9zx – 4y and –3xz + 5x – 2xy, then the answer is:

If we add, 7xy + 5yz – 3zx, 4yz + 9zx – 4y and –3xz + 5x – 2xy, then the answer is:

A. 5xy + 9yz +3zx + 5x – 4y

B. 5xy + 10yz +3zx + 15x – 4y

C. 5xy – 9yz +3zx – 5x – 4y

D. 5xy + 10yz +3zx + 5x – 6y