Two constitutional isomers having molecular formula C4H6O are both symmetrical in structure. In their infrared spectra, neither isomer when in dilute solution in CCl4 (used because it is nonpolar) has absorption in the 3600-cm-1 region. Isomer A has absorption bands at approximately 3080, 1620, and 700 cm-1. Isomer B has bands in the 2900-cm-1 region and at 1780 cm-1. Propose a structure for A and two possible structures for B.