This is a question I heard on a game show (they used
whom):
'Who did David become after he was fed the poison?'
OR
'Whom did David become after he was fed the poison?'
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Attempt at sentene inversion: David became whom/who after he was fed the poison.
I am struggling to invert this sentence into a statement. Generally the subject and verb are switched around, but I am struggling to determine the subject and verb in the sentence.
-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
David=subject
became=verb
whom=object
after he was fed the poison=prep phrase and adverbial clause
If this is correct, then technically my sentence inversion has not inverted the verb and subject................
Why would
DID be omitted in the sentence inversion?
I feel whom is the right answer, but I would like help with steps to get to this conclusion, please.

-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Thanks.