Suppose we have the relation schema R（A, B, C, D)with functional dependencies; F{A→B,B→C,

Suppose we have the relation schema R(A, B, C, D)with functional dependencies; F{A→B,B→C,C→D,D→A}, then R(A,B,C,D. at least is in(73).

A．1NF

B．2NF

C．3NF

D．BCNFThe construct eobegin Statement1; Statement2; coend means Statement1 and Statement2 are to be executed in parallel. The only two atomic actions in this construct are loading the value of a variable and storing into a variable. For the p