$(A)$ hydrazoic acid $N _3 H$, dissociates into $N _3$ - and $H +$. Due to the formation of hydrogen ion, it is an acid.

$(B)$ In $N_2H_4$, nitrogen easily donates it's lone pair, so it is a base.

$(C)$ $NH_2 Oh$ is basic because it has hydroxyl ions.

$(D)$ The compound trimethylamine, $\left( CH _3\right)_3 N$, is a weak base when dissolved in water.