The correct order of increasing basicity of the given conjugate bases ($\text{R}={\text{CH}}_3$) is:

1. A
   ${\text{RCOO}}^{-}<\text{HC}\equiv {\text{C}}^{-}<{\text{R}}^{-}<{\text{NH}}_2^{-}$
2. B
   ${\text{R}}^{-}<\text{HC}\equiv {\text{C}}^{-}<{\text{RCOO}}^{-}<{\text{NH}}_2^{-}$
3. C
   ${\text{RCOO}}^{-}<{\text{NH}}_2^{-}<\text{HC}\equiv {\text{C}}^{-}<{\text{R}}^{-}$
4. D
   ${\text{RCOO}}^{-}<\text{HC}\equiv {\text{C}}^{-}<{\text{NH}}_2^{-}<{\text{R}}^{-}$