According to given question,
A → @ , B → # , C → $ , D → % , E → ^ , M → & , N → * , O → α , S → β , R → γ , U → δ
Replace the each capital from given relationship for # α @ γ %, We will get
# → B
α → O
@ → A
γ→ R
% → D
Hence , the required answer will be BOARD.