Montporte Dungeon Exploration: Player Options

The map below displays the progress of the player characters after five sessions of play in the Montporte Dungeon. Here is the key to the map:
  • A=The current location of the player characters
  • B=A large kobold clan is known to live north of here and have archer guards posted at B
  • C=Unexplored corridors and rooms
  • D=Unopened doors
  • E=Entrance/exit to the dungeon
A couple of observations, based on the map:
  • The players have a lot of options. There are 12 unexplored corridors/rooms and 7 unopened doors for a total of 19 options for exploration. 
  • The players have done a good job of discovery in the center of the map, a result of sessions 1-4 focus on rescuing human hostages from a band of orcs. There appear to be nothing unexplored in the middle of the map.
  • The players have not found any additional levels.
  • The players have not discovered any additional entrances to the dungeon, although they have been told of a sinkhole that allows the kobold contingent (north of B on the map) access to the dungeon.
If you were the player characters, what would be your next move?