2. a. Give a necessary and sufficient condition for a decomposition of R into R1 and R2 to be lossless join. Very briefly explain why the condition is necessary and sufficient. [10 points] b. Given F= {AB, AC, CGH, CGI, BH), set of functional dependencies on R(A, B, C, G, H, I), check if A is a candidate key of R. [10 points]