The suggested answer is A.
The share tray allows you to move and duplicate content to and from the main and presentation displays.
✑ To show the share tray, tap Share.
✑ To add content to the conference, drag the content from the share tray to the presentation area.
✑ To remove content from the conference, drag the content from the presentation area to the share tray.
Reference: http://www.cisco.com/c/dam/en/us/td/docs/telepresence/ix_sw/8_x/user/guide/ix-8-1-ug.pdf