Is benim optional or required in this sentence?
it is optional (but slightly preferred)
Can we say "centilmen"?
no centilmen is only used as an adjective. it means kind (for men usually towards women)
Is it inappropriate to say "O" instead of "Şu"? I'm hoping my other mistake is why my answer was counted wrong. :)
It wouldn't be inappropriate at all :) Must have been your other mistake!
My hero <3 Thank you!