D. has already written / has been checking it out
Feedback 1. 'Already' shows us that the action is complete and we see the result in the present. This is why the Present Perfect is an appropriate tense for the first part of the sentence. 2. 'For two hours' and 'Don't interrupt her' shows that the process (has been checking it out) is still in progress. It started in the past and continues up in the present, therefore we use the Present Perfect Continuous.