The 1h nmr spectrum of compound a (c15h14o) shows only two signals: a multiplet at 7.15 ppm and a singlet at 3.55 ppm in a 5: 2 ratio. the ir spectrum has no absorption in the 3200–4000 cm–1 region, but strong peaks can be found near 1700 cm–1. compound a reacts with nabh4 followed by acidification to give compound b of the molecular formula c15h16o. the reaction of a with ch3mgbr, and then with h3o+, gives c, with a molecular formula of c16h18o. suggest structures for b and c.