Made easy test series2019 database closed

Question

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 contain 100000 tupples stored in a sequential file sorted on attribute B. Each block can hold 10 R tupples or 10 S tupples. Which one of the following index is most appropriate for answering query (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

Comments

Option D should be a correct answer... 
The concept is in the data file attribute on which the entries are in sorted order use each block anchor as index entry...

Not all entries... If you are forced to store all data file entries then DENSE otherwise SPARSE