guarantee(s) the access structure is always balanced when a lot of updates such as insertions and deletions of file records occur. Multilevel index B-tree/B+-tree Multi-Way search tree Dynamic hashing has the least number of block accesses to search and retrieve a record (Assume the number of records is very big). Cluster index Secondary index B-tree/B+-Tree Primary index uses(use) the less number of blocks to hold necessary index entries (Assume the number of records is very big). a. Primary index c. Secondary index Of. None of a., b., and c. e. All of a., b., and c. d. Both a. and b. O b. Cluster index is the non-dense index. O . a. Primary index d. Both a. and b. c. Secondary index b. Cluster index Of. None of a., b., and C. e. All of a., b., and c