The correct option is D (x2−y2+xy)(x2−y2−xy)
Given, the expression is
x4+y4−3x2y2.
the above expression can be written as,
(x2)2+(y2)2−2x2y2−x2y2
=(x2)2−2x2y2+(y2)2−x2y2
Using the identity
(a−b)2=a2−2ab+b2,we get,
(x2−y2)2−(xy)2
[Using identity: a2−b2=(a−b)(a+b)]
=(x2−y2+xy)(x2−y2−xy)