Consider two relations R1(A, B) with the tuples (1, 5), (3, 7) and R2(A, C) = (1, 7), (4, 9). Assume that R(A, B, C) is the full natural outer join of R1 and R2. Consider the following tuples of the form (A, B, C): a = (1, 5, null), b = (1, null, 7), c = (3, null, 9), d = (4, 7, null), e = (1, 5, 7), f = (3, 7, null), g = (4, null, 9). Which one of the following statements is correct?
1
R contains a, b, e, f, g but not c, d.
2
R contains all of a, b, c, d, e, f, g.
3
R contains e, f, g but not a, b.
4
R contains e but not f, g.
5
Question Not Attempted