who or whom

In this sentence should it be who or whom?

e.g. I can’t believe it you hired who/whom?!

In theory I think it should be ‘whom’.

We use ‘whom’ when we are talking about the object of the sentence.

So:
[i]
Speaker 1: I hired John. (John = the object of the sentence)

Speaker 2: I can’t believe it. You hired whom?[/i]

Bit it’s unusual to use whom, especially when speaking. Most people just use who.

Thank you!

No problem