During a project's execution phase, the team faced a setback in one of the deliveries...

The described behavior—agreeing externally while internally opposing—matches the accommodative (also known as smoothing or yielding) conflict resolution style. This approach involves one party giving in to maintain harmony, even at the cost of their own interests.

According to the PMI’s conflict resolution techniques:

Accommodating (or smoothing): One party gives in to maintain harmony.

Avoiding: Withdrawing from conflict and not addressing it.

Collaborating: Working together to find a win-win solution.

Competing (Combative): Pursuing one's own concerns at the other’s expense.

The team members in the scenario were not withdrawing (so not Avoidant), and certainly not arguing (so not Combative). They weren't actively resolving either, which rules out Collaborative. Thus, the correct resolution style is Accommodative.