B.
If your daughter truly has ADHD it won't effect anything.
You can start by eliminating all red dyes and sugar.
Only people with an allergy to eliminated foods will see a difference in behavior.
I know someone that had great success with it and again I know someone it didn't help at all, we tried diet changes eliminating things that are the big triggers. But nothing worked.
My ADHD child is on medication after much deliberation and trying other things. Nothing else worked.
With her medication it helps her stop and think before she reacts. it's not a cure all. But it helps the behavior modification system we use to work better.
Pick up " Taking charge of ADHD" by Barkley for you and pick up
" How to slow down and pay attention " by Nadeau and Dixon for your daughter. The first gives you techniques and tips on how to cope and manage ADHD the second does the same for her. From everything from managing anger to cleaning her room.