"This is a central question for doctors."
Translation:זאת שאלה מרכזית בשביל רופאים.
What is this זוהי we see instead of זאת at the beginning of one of the correct options in the multiple choice question?
That is another to say "this is" when the subject is feminine (if the subject is masculine you can use זהו). There is not difference between זאת and זוהי in this case.