Decreasing order of basic strength: NH2- >OH- > CH3-CH2- > H-C=C-
OH- is a conjugate base of H2O and NH2- is a conjugate base of NH3. H2O is stronger acid than NH3 so OH- is a weaker base than NH2- .
CH3-CH2- is an alkane H-C=C- alkyne in alkynes S character is more so acidic nature is more.