Given the relation R and the following functional dependencies,answer the following questions. R(A, B, C, D, E) All attributescontain only atomic values. FD1: A ? BC FD2: CD ? E FD3: B ? D FD4: A ? E (a) Compute A+, the attribute closure of attribute A. (b) List the candidate keys of R. (c) What’s the highest normal form that R satisfies and why? (d) If R is not already at least in 3NF, then normalize R into3NF and show the resulting relation(s) and their candidate keys.Your decomposition should be both join-lossless anddependency-preserving. If R is already in 3NF, just list thecandidate keys of R. (e) Is your answer to (d) also in BCNF? Why or why not? . . .