The correct option is A diethyl ether
The general method for the synthesis of ether is Williamson ether synthesis, involves nucleophilic displacement of a halide ion or other good leaving group by an alkoxide ion.
This is the industrial process for making ethers.
Sodium ethoxide is heated with ethyl iodide to form diethyl ether.
The reaction is as follows:
C2H5ONa+C2H5I→C2H5−O−C2H5+NaI
Hence, the correct answer is option (a).