1. Identify the confirmatory test for aromatic primary amines

Aromatic primary amines such as aniline are commonly confirmed by the diazotisation followed by azo dye formation test.

2. Step 1: Diazotisation reagent

An aromatic primary amine reacts with nitrous acid at low temperature $(0-5^\circ \mathrm{C})$ to form a diazonium salt.

Since nitrous acid is unstable, it is generated in situ using: $\mathrm{NaNO_2 + HCl}$

So reagent (A) must be nitrous acid generation conditions, i.e. $\mathrm{NaNO_2/HCl}$ at $0-5^\circ C$.

3. Step 2: Coupling reagent

The diazonium salt then couples with an activated aromatic compound such as $\beta$-naphthol in alkaline medium to form a brightly colored azo dye, which is the confirmatory observation.

So reagent (B) must be alkaline $\beta$-naphthol.

4. Conclusion

Thus the confirmatory test uses:

• (A): $\mathrm{NaNO_2 + HCl}$ at low temperature
• (B): alkaline $\beta$-naphthol

Hence, the correct option is the one corresponding to these reagents, which is given as Option A.

5. Comparison with stored answer

Stored correct answer = A

My derived answer = A

So they agree.