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

In the chemical reaction,
CH₃CH₂NH₂ + CHCl₃ + 3KOH $$\to$$ (A) + (B) + 3H₂O, the compound (A) and (B) are respectively

An organic compound having molecular mass 60 is found to contain C = 20%, H = 6.67% and N = 46.67% while rest is oxygen. On heating it gives NH₃ along with a solid residue. The solid residue give violet colour with alkaline copper sulphate solution. The compound is

Amongst the following the most basic compound is