Which statement is true?

An employee list can give the departments and job titles of employees.
A product list can include names and addresses of buyers of the product.
A medical record can include consumer buying behaviors of prescriptions.
A market research report can give names of employees of a compan

Eva has many contacts on the professional networking site she uses which contacts are considered second degree

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)?