You enter a room and find ten knights. You know that five of them belong to the Lie Clan, and lie all the time. Five of them belong to the Truth Clan. They never lie. You do not know whom of the belong to which clan.

Arvid: Fredrik and Henrik belong to the same clan.
David: No. They do not. Fredrik belongs to the same clan as Ingvar, by the way.
Jakob: Gustav and Henrik belong to the same clan.
Ingvar: I belong to the same clan as Jakob.
Erik: I belong to the same clan as Bengt.
Bengt: I do not belong to the same clan as Charlie.
Ingvar: I belong to the same clan as Henrik.

Who belongs to the Truth Clan? Answer with the capital letters in their names, in alphabetical order.
Answer here