若\( \overrightarrow{AB}=2\overrightarrow{BC},\)则下列各式中正确的是 ( )
A.\( \overrightarrow{AC}=2\overrightarrow{BC}\)
B.\( \overrightarrow{AC}=\frac{2}{3}\overrightarrow{BC}\) C.\( \overrightarrow{AC}=3\overrightarrow{BC}\) D.\( \overrightarrow{AC}=\frac{4}{3}\overrightarrow{BC}\)