Which of the following liberate an alkane when treated with $\mathrm{CH}{}_3\mathrm{MgBr}$ in dry ether? (Consider only the acid-base reaction.)

Ethanol (O-H), propyne (terminal sp C-H) and ethanoic acid (O-H) all have acidic hydrogen and protonate $\mathrm{CH}{}_3\mathrm{MgBr}$ to give $\mathrm{CH}{}_4$. Dimethyl ether has no acidic hydrogen and only coordinates to Mg.