I have not heard 'What are you busy about?' before and find it unnatural. 'What are you busy with?' as in 'What are you busy with this morning?' is fine as a question, but I don't think you would ...

I have not heard 'What are you busy about?' before and find it unnatural. 'What are you busy with?' as in 'What are you busy with this morning?' is fine as a question, but I don't think you would ...