I think that she should do it.

Explanation

- The original sentence "I think that she should do it" is in active voice, where the subject "she" performs the action of doing.- To convert it to passive voice, we need to make the action (doing) the subject, and the action is performed on it. Hence, the correct passive voice construction is "I think that it should be done by her".- This construction emphasizes the action, rather than the person performing the action (she).