What is the decreasing order of strength of the bases OH-,NH2-,H-C≡C-and CH3-CH2-?

Their conjugate acids are H-OH,NH3, H-C≡C-H and CH3-CH3 Their acidic character are H-OH>CH≡CH>NH3>CH3-CH3. A strong acid has a weak conjugate base. Hence, the strengths of bases will beCH3-CH2->NH2->H-C≡C->OH-