Which two statements regarding OLTP systems are true? (Choose two)

A. Use literals for optimally shared SQL rather than bind variables to keep the overhead of parsing to a minimum.
B. To avoid the performance load of dynamic space allocation, allocate space explicitly so tables, clusters and indexes.
C. B-tree indexing is preferred to bitmap indexing, because of locking issues affecting DML operations.
D. Use hash clusters especially on tables that are heavily inserted into, because of the use of space and the number of blocks that need to be visited.
E. Use application code to enforce business rules instead of constraints, because constraints are extremely expensive to process.

Please advise and explain, thx