a) [15 marks] Consider a relation schema N (R, F) where R = {A, B, C, D} and F = {BC, CDA, BD}. Perform the following tasks. Justify your answers. 1) Identify all keys for N. Show your process. 2) Identify the highest normal form (1NF, 2NF, 3NF, BCNF) that N satisfies. 3) If N is not in 3NF, compute a lossless transformation into a set of 3NF relation schemas that preserve attributes and functional dependencies. 4) Verify explicitly that your result has the lossless property, satisfies 3NF, and that all attributes and functional dependencies are preserved.