Hadoop is a(n):

a) NoSQL database technology that stores both data and procedures acting on the data as objects.
b) high-speed platform used to analyze large data sets.
c) pre-configured hardware-software system designed for analyzing big data.
d) Hadoop can process large quantities of any type of data, including video and Twitter feeds.

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)?