Final answer:
Discuss the situation with Twila and handle it informally, considering her previous good behaviors.
Step-by-step explanation:
As Twila's probation officer, you should discuss the situation with her and handle it informally.
Given her previous track record of being drug-free and actively participating in treatment and NA meetings, it is important to consider this as an isolated incident.
By addressing the issue informally, you can emphasize the importance of maintaining her sobriety and remind her of the consequences if similar situations occur in the future.