 Solution

The phenolic O–H is most acidic; the benzylic CH2 adjacent to the amide carbonyl is second. Phenolic deprotonation gives a phenoxide stabilized by resonance in chemistry. Removing an alpha-amide C–H gives an enolate/carbanion stabilized by the carbonyl and the adjoining aryl group, but requires substantially stronger basicity for a comparable equilibrium concentration. The morpholine nitrogen is an acylated tertiary amide nitrogen and has no N–H proton. The other morpholine and aromatic C–H positions do not have the same direct carbonyl stabilization.