Step 1: Trace each salt to its parent acid and base
NH$_4$NO$_3$: weak base NH$_4$OH with strong acid. CH$_3$COONa: weak acid with strong base. NH$_4$CN: weak base with weak acid. NaNO$_3$: strong base NaOH with strong acid HNO$_3$.
Step 2: Decide
Only the last pair has no weak parent, so only NaNO$_3$ is free from hydrolysis. Answer (D).
Final Answer:
Only sodium nitrate comes from a strong acid and strong base, option (D).
\[ \boxed{\text{NaNO}_3} \]