Multiple Choice Which of the following explains why the engineering design process is considered cyclical? O It takes many years for an engineer to earn a PE license. O Engineers may face constraints that will force them to redesign a project from the beginning O A design and its prototype are always designed midway through the process. O Projects with large teams of interdisciplinary individuals can be very complex.

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)?