Answer

`b`

Explanation

`C_(2)H_(45)O^(theta)` will attract the proton from phenol converting the latter into phenoxide ion. This would then make nuclephilic attack on the methylene carbon of alkyl iodine. But `C_(2)H_(5)O^(theta)` is an excess. `C_(2)H_(5)O^(theta)` is a better nucelophiliic than `C_(6)H_(5)O^(theta)` (phenoxide) ion since in the former, teh negative charge is localised over oxygen and in the latter, it is delocalised in the ring. So it `C_(2)H_(5)O^(theta)` ion that would make muclephilic attack at ethyl iodie t give diethyl ether (WIllamon's symthesis).