Some jobs have a greater risk of workplace violence. which of the following are factors that lead to an increased risk of workplace violence? a. all of the answer choices are correct b. making deliveries and having extensive contact with the public. c. working in a high-crime area. d. working in places where alcohol is served. e. working late night or early morning hours and handling money or other valuables.

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)?