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

• A. \[7|\overset{\to }{\mathop{a}}\,\times \overset{\to }{\mathop{b}}\,{{|}^{2}}\]
• B. \[42|\overset{\to }{\mathop{a}}\,\times \overset{\to }{\mathop{b}}\,{{|}^{2}}\]
• C. 0
• D. None of these