To Show Comments and Revisions at the Left Side of the Document

To show comments and revisions at the left side of the document, click ____.

A) Reviewing Pane button arrow in the Tracking group, and then click Reviewing Pane Horizontal
B) Show Markup in the Tracking group, and the click Comments
C) Track Changes button in the Tracking group, and then click Change Tracking Options
D) Reviewing Pane button arrow in the Tracking group, and then click Reviewing Pane Vertical