1. Understand the situation

A balloon contains helium at $T = 32^\circ C, \qquad P = 1.7\,\text{atm}$ and then it bursts.

Immediately after bursting, the gas expands very rapidly into the surroundings.

2. Decide whether the process is reversible or irreversible

A reversible process is infinitely slow and occurs through a continuous sequence of equilibrium states.

When a balloon bursts, the expansion is:

• sudden,
• very fast,
• not quasi-static,
• accompanied by pressure imbalance.

So the process is irreversible.

3. Decide whether the process is adiabatic or isothermal

• Isothermal means temperature remains constant during the process, which generally requires enough time for heat exchange with surroundings.
• Adiabatic means no heat is exchanged.

Since the expansion occurs immediately after bursting, the process is extremely fast, so there is essentially no time for heat transfer between helium and surroundings.

Hence, $Q \approx 0$ so the process is adiabatic.

4. Conclusion

The expansion immediately after the balloon bursts is: $\boxed{\text{Irreversible adiabatic}}$

So the correct option is A.

5. Comparison with stored answer

Stored correct answer: A
Derived answer: A

They match.