Which of the following is not a user interface?

How does a policy manual an organization? a. it boost productivity. b. it create awareness in employees about the organization’s values. c. it employees achieve targets. d. it safeguards the organization from liabilities.

Effective character encoding requires standardized code. compatible browsers. common languages. identical operating systems.

Suppose there is a relation r(a, b, c) with a b+-tree index with search keys (a, b).1. what is the worst-case cost of finding records satisfying 10 < a < 50 using this index, in terms of the number of records n1, retrieved and the height h of the tree? 2. what is the worst-case cost of finding records satisfying 10 < a < 50 and 5 < b < 10 using this index, in terms of the number of records n2 that satisfy this selection, as well as n1 and h defined above? 3. under what conditions on n1 and n2, would the index be an efficient way of finding records satisfying the condition from part (2)?