Unsubstituted organic acids are weak (or) very weak acids. Which of the following compound is most acidic?

Electronegativity of Csp>Csp2>Csp3. Greater the stability of the anion after the loss of proton stronger is the acid.More electronegative atom can hold negative charge most readily. ∴stability  of  HC≡C⊝>CH3−C≡C⊝>CH2=C⊝H>CH3−C⊝H2    stability   of  CH≡C⊝>CH3−C≡C⊝  because+I effect of -CH3 group intensifies the negative charge and destabilizes the carbanion.