Final answer:
In a civil trial, a witness is not allowed to provide hearsay evidence, which means they cannot testify about something they did not personally observe, like what their best friend saw happen.
Step-by-step explanation:
Based on the understanding of the role of a witness in a civil trial, a witness is not allowed to answer questions based on what someone else saw happen, which is referred to as hearsay. This is because hearsay is typically inadmissible in court unless it falls under certain exceptions, such as being an admission of guilt or a dying declaration. Witnesses must provide direct knowledge and evidence based on their own experiences, not those of others. Therefore, option D) 'Answer questions about something her best friend saw happen' is something a witness is not allowed to do in a trial.
Witnesses need to provide factual and firsthand accounts during a trial. They can be asked questions by lawyers from both sides, discuss events they have personally witnessed, and provide details on their relationship with the parties involved in the case. However, their testimony must be relevant and based on their own observations, which helps ensure the integrity and reliability of the legal proceedings.