Iodoform can be obtained on warming $NaOH$ and iodine with

In the esterification reaction of $p$-toluic acid with methanol $(CH_3^{18}OH)$,the product $A$ is:

Isopropyl alcohol on oxidation gives

Product $(B)$ of the given reaction is:

The compound $A$ on treatment with $Na$ gives $B$,and with $PCl_{5}$ gives $C$. $B$ and $C$ react together to give diethyl ether. $A, B$ and $C$ are in the order

Which one of the following gases is liberated when ethyl alcohol is heated with methyl magnesium iodide?