The gas leaked from a storage tank of the Union Carbide plant in Bhopal gas tragedy was:

An organic compound A upon reacting with $$N{H_3}$$ gives $$B.$$ On heating $$B$$ gives $$C.$$ $$C$$ in presence of $$KOH$$ reacts with $$B{r_2}$$ to given $$C{H_3}C{H_2}N{H_2}2.$$ $$A$$ is :

In the chemical reactions,



the compounds $$'A'$$ and $$'B'$$ respectively are

Which one of the following is the strongest base in aqueous solution?