Select the correct text in the passage. Identify who can apply for a graduate certificate.

Pete has a technical certificate and is a robotics technician. Melinda completed her undergraduate certification course last week while studying for her undergraduate degree course. Brian is fresh out of high school and wants to be a robotics automation engineer. Timothy has a bachelor’s degree in mechanical engineering and works in a robotics firm.

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)?