Let $\overrightarrow {a}=a_1\hat i+a_2 \hat j+a_3 \hat k$ Assertion (A): The identify $|\overrightarrow a \times \hat i |^2+|\overrightarrow a \times \hat j|^2+|\overrightarrow a \times \hat k| ^2=2 | \overrightarrow a |^2$ holds for $\overrightarrow {a}$. Reason (R): $\overrightarrow {a} \times \hat i =a_3 \hat j- a_2 \hat k, \overrightarrow a \times \hat j= a_1 \hat k- a_3 \hat i, \overrightarrow a \times \hat k=a_2 \hat i- a_1 \hat j$ Which of the following is correct ?