Please answer the question which I have attached.............. ......

es. Although, it will sound very formal when spoken, you may be able to pull it off if it were written.

Spoken wise, you can simplify the sentence just as normal humans do yet keep it formal. Some examples:

‘As requested, I have attached the details for your consideration.’

‘I have attached the requested details for your consideration.’

‘Attached are the details that you have requested for consideration.’

‘The documents are attached as requested.’