A. It is recommended that you select/bcp out all the relevant data and then recreate the objects concerned. However, if you want to attempt a rebuild of the extents then make a backup first, and then try the following after putting the database into single-user mode first :-
dbcc rebuildextents (@db_id, @object_id, @index_id)
@db_id Id of the database
@object_id Id of the object to be rebuild
@index_id Id of the index to be rebuild
Alternatively you could just rename the object and leave it in the database with a dummy name - you won't be able to drop the object.