如图,已知平面四边形 $\mathit{ABCD},\mathit{AB}\perp \mathit{BC},\mathit{AB}=\mathit{BC}=\mathit{AD}=2,\mathit{CD}=3,\mathit{AC}$ 与 $\mathit{BD}$ 交于点 $O$ . 记 $I_1=\overrightarrow{\mathit{OA}}\cdot \overrightarrow{\mathit{OB}},I_2=\overrightarrow{\mathit{OB}}\cdot \overrightarrow{\mathit{OC}},I_3=\overrightarrow{\mathit{OC}}\cdot \overrightarrow{\mathit{OD}}$ , 则（    )

A．	$I_1<I_2<I_3$
B．	$I_1<I_3<I_2$
C．	$I_3<I_1<I_2$
D．	$I_2<I_1<I_3$