$3+\dfrac{1}{1+\dfrac{1}{5+\dfrac{1}{16}}}=\left( \textbackslash{} \textbackslash{} \textbackslash{} \textbackslash{} \right).$ 
选项为:A:$\dfrac{307}{97}$  B:$\dfrac{16}{97}$  C:$\dfrac{145}{16}$  D:$\dfrac{372}{97}$  请回答其中一个选项.