If \[\overrightarrow{OA}=\vec{a};\overrightarrow{OB}=\vec{b};\overrightarrow{OC}=2\vec{a}+3\vec{b}\,;\] \[\overrightarrow{OD}=\vec{a}-2\vec{b}\], the length of \[\overrightarrow{OA}\] is three times the length of \[\overrightarrow{OB}\] and \[\overrightarrow{OA}\] is perpendicular to \[\overrightarrow{DB}\] then \[\left( \overrightarrow{BD}\times \overrightarrow{AC} \right).\left( \overrightarrow{OD}\times \overrightarrow{OC} \right)\] is

• A. \[7{{\left| \vec{a}\times \vec{b} \right|}^{2}}\]
• B. \[42|\vec{a}\times \vec{b}{{|}^{2}}\]
• C. 0
• D. None of these