Here is your answer:
Your answer is D as many as you can comfortably fit.
Your answer is D.
Many are biased as to who they treat and how well they treat patients (mostly based on age/race/gender/etc).
I'm not too sure about this. However, I would say that it is Ok to say attached is the assignment. It seems wrong, but to make it seem more natural, maybe try adding extra words like requested.
Can you put up the passage? We can’t see anything?