Phlorizin is obtained from the root bark of apple, pear, cherry, and plum trees. It has the molecular formula C21H24O10 and yields a compound A and D-glucose on hydrolysis in the presence of emulsin. When phlorizin is treated with excess methyl iodide in the presence of potassium carbonate and then subjected to acid-catalyzed hydrolysis, a compound B is obtained. Deduce the structure of phlorizin from this information.