$\mathrm{R}-\mathrm{OH}\underset{\mathrm{low} \mathrm{temperature}}{\overset{\mathrm{conc}.{\mathrm{H}}_2{\mathrm{SO}}_4}{\to }}\mathrm{R}-\mathrm{O}-\mathrm{R}$

Among the following alcohols, the above method of preparation is most suitable for 

The above method is suitable for the preparation of symmetrical ethers from 1º alcohols.

(1) and (2) are mixed ethers. They cannot prepared in good yields.

(3) cannot prepared because the starting material is (CH₃)₃C-OH.

It undergoes dehydration to give isobutene as major product.

(4) C₂H₅-O-C₂H₅ is obtained from two moles of primary alcohol, C₂H₅OH.