Which of the following reactions will give t-butyl ethyl ether by Williamson synthesis?

The correct answer is option (1).

This is Williamson ether synthesis.

Williamson ether synthesis is a type of nucleophilic substitution reaction. It is the most versatile method for the synthesis of ether using a primary alkyl halide and an alkoxide. The alkoxide ion attacks the alkyl halide substituting it with an alkoxide group. Usually, sodium or potassium metal dissolves in alcohol to generate the alkoxide.