An aqueous solution of NaOH is added to ether layer C. The mixture is shaken and left for a while to give two layers, ether layer E and aqueous layer F. The separated aqueous layer F is mixed with ether and dilute hydrochloric acid. After shaking the mixture, two layers (ether and aqueous layers) are observed. Which of the compounds 1) to 4) is included in the final ether layer?