Explanation:

- Option 1: Consent/compromise decrees

- Res-judicata may not apply because these decrees are often based on mutual agreement rather than judicial determination.

- Option 2: Dismissal in default

- Res-judicata doesn't apply here since the case is not decided on its merits but dismissed because of non-appearance, which leaves the door open for re-filing.

- Option 3: Both (a) & (b)

- Both scenarios often do not invoke res-judicata because neither results from a full, merit-based judicial decision.

- Option 4: Neither (a) nor (b)

- This suggests res-judicata would apply to both, which is generally incorrect.