I know I marked this as an "arts" question, but I really need help figuring this out. I have asked my teacher for help, but all she gave me was a video on this. I still do not understand what they mean by "which scale degree" is appropriate for the given chord. I know that the given chord is a F chord, and the scale is an F major scale. (the B key is flat), but I don't get what and how they want me to figure this out. I'm really confused :/ If someone understands music, please help me, I'm in desperate need!!!!

Your teacher is tweakin. But here’s what I’ve got.
The key that you are in is actually Fmajor With there only being one flat in the key (Bb). Personally I would be an E there to make it a major 7th chord. But because that isn’t an option go with letter B. Here is why. Your teacher has given you an Fmajor triad consisting of the notes F A C. Without changing the written chord I would double the bass note aka the F. But that’s also not an option. So you move onto what the next best option is and that is to double the A.
What class is this...? Because this whole question is bad.