A blimp needs to be moored when not flying because plenty of space is needed so the blimp has to be free. They have to be moored by the front end to a tall mast on a truck specially equipped for this purpose.
I have Aviation History so I kinda of undertsnd.
HOPE THIS HELPS. :)
Answer:
pigeons r government spies
Explanation:
look it up
It would be between A or D but I would say D