1. A cost -based optimized stores all the following statistics for a table except

a. the number of users authorized to read the table

b. the number of rows in the table

c. the average length of a row

d. the amount of unused space per block/page

2. in optimizied , sql queries are normally translated into a lower-level representation in

a. first-order predicate calculus

b. QBE

C. relational algebra

d. OQL