A silica TLC analysis of a three-component reaction mixture in 80:20 hexane:ethyl acetate gives the following Rf values: unknown X = 0.70, unknown Y = 0.48 (spot shows pronounced tailing), unknown Z = 0.15. Standards run on the same plate give: benzaldehyde 0.71, benzoic acid 0.47 (spot tails), and benzyl alcohol 0.16. Assign identities to X, Y, and Z.