database systems, normal forms

Consider the relations R with the attributes A, B, C, D, E and the corresponding functional depen- dencies F. Find all possible candidate keys for each scenario and decide, if the corresponding rela- tion fulfills the 1NF, 2NF or 3NF. Hint: You can assume that all attribute values are atomic. a) (0.5 points) R(A, B, C, D, E) with F = {D + E, A + BC, BC + AD} b) (0.5 points) R(A,BC,D,E) with F = { DB.C + AD, BEC} c) (0.5 points) R(A,B,C,D,E) with F = { BACE, EDADB} d) (0.5 points) R(A,B,C,D,E) with F = {AE+D, BCE + A} e) (0.5 points) R(A, B, C, D, E) with F = {CDE BABE CD}