The correct option is B (5n+6m)(5n−6m)=(5n)2−(6m)2
The given identity is (5n+6m)(5n−6m)=(5n)2−(6m)2
Area of full square = area of pink rectangle + area of blue rectangle.
i.e., (5n)2−(6m)2=5n(5n−6m)+6m(5n−6m)
(5n)2−(6m)2=(5n+6m)(5n−6m)
So, (5n+6m)(5n−6m)=(5n)2−(6m)2 is used in the diagram.