RCOO⁻<HC=C⁻<R⁻<NH₂
R⁻<HC≡C⁻<RCOO⁻<NH₂
RCOO⁻<NH₂<HC≡C⁻<R⁻
RCOO⁻<HC≡C⁻<NH₂<R⁻
In basicity, more available the electrons, the more readily they can be donated to form a new bond to the proton and, and therefore the stronger base. If bronsted acid is a strong acid then its conjugate base is a weak base and vice versa. So, correct order of increasing basic strength is RCOO⁻<HC≡C⁻<NH₂<R⁻