If $\vec{a}$ and $\vec{b}$ are two non zero vectors, then which of the following is correct :

A. $\vec{a}×\vec{b}=\vec{0}$ if and only if $\vec{a}$ is perpendicular to $\vec{b}$.

B. $\vec{a}×\vec{b}$ is vector.

C. $\vec{a}×\vec{b}=|\vec{a}||\vec{b}|cos\theta \hat{n}$

D. If $\theta =\frac{\pi}{2}.|\vec{a}×\vec{b}|=|\vec{a}||\vec{b}|$

Choose the correct answer from the options given below :

B and D only