We present a study of resonances in exclusive decays of B mesons to D̅ (*)D(*)K. We report the observation of the decays B→D̅ (*)Ds1+(2536) where the Ds1+(2536) is reconstructed in the D*0K+ and D*+KS0 decay channels. We report also the observation of the decays B→ψ(3770)K where the ψ(3770) decays to D̅ 0D0 and D-D+. In addition, we present the observation of an enhancement for the D̅ *0D0 invariant mass in the decays B→D̅ *0D0K, at a mass of (3875.1-0.5+0.7±0.5) MeV/c2 with a width of (3.0-1.4+1.9±0.9) MeV (the first errors are statistical and the second are systematic). Branching fractions and spin studies are shown for the three resonances. The results are based on 347 fb-1 of data collected with the BABAR detector at the PEP-II B factory.