Consider two relations R(A,B,C) and S(B,D) with R contains 5000 tupples stored in a sequential file sorted on attribute A and S contains 100000 tupples stored in a sequential file sorted on attribute B. Each block can hold 10R tupples or 10S tupples.which one of the following index is most appropriate for answering query R⨝S?(Assume index always stored in memory).
A) a dense index on R.B
B) a sparse index on R.B
C) a dense index on S.B
D) a sparse index on S.B
