20 Select the correct answer.
Why is it important to use effective search terms when looking for information on the web?
ОА.
because ineffective search terms can slow down the search engine
OB.
to avoid having to navigate through irrelevant results
OC.
to avoid having to choose from too many relevant results
OD.
because ineffective search terms can bring up too few results
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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)?