Answer: organize a face-to-face discussion with the team.
Explanation:
For Roberta to convey her message clearly, the most appropriate way will be for her to organize a face-to-face discussion with the team.
Since she wants to establish an open communication culture, having a face to face discussion is essential. In this case, the team shares their ideas and are more engaged. The team then understands what is required of them and works towards achieving company goals.