If a2 + b2 = 2 and c2 + d2 = 1, then the value of (ad - bc)2 + (ac - bd)2 is?

Answer: Option D

$$\begin{array}{rl}& a^2+b^2=2\\ & c^2+d^2=1\\ & \text{Put values of }a,b,c,d\\ & \text{Take ,}a=b=1\\ & c=1\\ & d=0\\ & \Rightarrow {\left(ad-bc\right)}^2\text{ + }{\left(ac-bd\right)}^2\\ & \Rightarrow {\left(0-1\right)}^2+{\left(1+0\right)}^2\\ & \Rightarrow {\left(-1\right)}^2+{\left(1\right)}^2\\ & \Rightarrow 2\end{array}$$