Arrange the following in decreasing order of their boiling points.

The boiling point of $(\mathrm{A})$ alcohol is highest due to $\mathrm{H}$-bonding. Out of primary (B), secondary (D) and tertiary amines (C), the boiling point in decreasing order is Primary amine $>$ Secondary amine $>$ Tertiary amine as intermolecular association decreases in same order, being highest in primary amine and least in tertiary amine due to steric hindrance. $\therefore$ The correct decreasing order of boiling point in given compound is A $>$ B $>$ D $>$ C.