Mark against the correct answer in each of the following:

Mark $(\sqrt{)}$ against the correct answer in each of the following:

If $|\vec{a}|=2,|\vec{b}|=7$ and $(\overrightarrow{\mathrm{a}} \times \overrightarrow{\mathrm{b}})=(3 \hat{\mathrm{i}}+2 \hat{\mathrm{j}}+6 \hat{\mathrm{k}})$ then the angle between $\overrightarrow{\mathrm{a}}$ and $\overrightarrow{\mathrm{b}}$ is A. $\frac{\pi}{6}$

B. $\frac{\pi}{3}$

C. $\frac{2 \pi}{3}$

D. $\frac{3 \pi}{4}$