I think it will be MM & AD. It would be a huge slap in the face for MM not to be captain as a 4 year starter.
AD has bided his time and been a team player throughout his career at LU, and became a solid contributor and starter last year. I think to choose an underclassmen like CS who has a similar role on the team is unlikely if there are only two captains. I do think it is possible there is a third captain this year though.