1 and 4 are my picks, because I don't think he is smart or clever enough to do 2 or 3 without involving more people than able to keep such an act secret.
There's also the old standby of "he just grabbed jive and didn't know what he took". After all, people had to restore shredded documents he was supposed to retain for the National Records.
However, it probably doesn't look good that he seemed to ignore repeated requests for those documents to the point the FBI had to execute a search warrant, so that kicks it up to intentional obstruction of some sort.
There's also the old standby of "he just grabbed jive and didn't know what he took". After all, people had to restore shredded documents he was supposed to retain for the National Records.
However, it probably doesn't look good that he seemed to ignore repeated requests for those documents to the point the FBI had to execute a search warrant, so that kicks it up to intentional obstruction of some sort.