Cho \(\left( {{\Delta _1}} \right):\,\,\dfrac{{x - 1}}{2} = \dfrac{{y - 1}}{3} = \dfrac{z}{1},\,\,\left( {{\Delta _2}} \right):\,\,\dfrac{{x - 3}}{1} = \dfrac{{y - 1}}{1} = \dfrac{{z - 1}}{2}\). Khi đó \(\cos \angle \left( {{\Delta _1};{\Delta _2}} \right)\).
A.\(\dfrac{7}{{\sqrt {83} }}\)   
B.\(\dfrac{7}{{\sqrt {84} }}\)   
C.\(\dfrac{7}{{\sqrt {82} }}\)   
D.\(\dfrac{1}{4}\)

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