Đáp án đúng: D
Cả A, B và C.
$\begin{array}{l}\left\{ \begin{array}{l}\xrightarrow{BTKL}44{{n}_{C{{O}_{2}}}}\,+\,18{{n}_{{{H}_{2}}O}}\,=\,{{m}_{ankan}}\,+\,{{m}_{{{O}_{2}}}}\,=47\\\xrightarrow{BTNT\,O}\,2{{n}_{C{{O}_{2}}}}\,+\,{{n}_{{{H}_{2}}O}}\,=\,2{{n}_{{{O}_{2}}}}\,=\,2,3\end{array} \right.\,\Rightarrow \,\left\{ \begin{array}{l}{{n}_{C{{O}_{2}}}}\,=\,0,7\,mol\\{{n}_{{{H}_{2}}O}}\,=\,0,9\,mol\end{array} \right.\\\Rightarrow \,{{n}_{ankan}}\,=\,{{n}_{{{H}_{2}}O}}\,-\,{{n}_{C{{O}_{2}}}}\,=\,0,2\,mol\,\Rightarrow \,\overline{C}\,=\,3,5\end{array}$
⟹ có 1 ankan ít hơn 3,5C và 1 ankan nhiều hơn 3,5C ⟹ cả 3 phương án đều thỏa mãn