Your program analyzes complex data. To share your results, you are going to write text to a file in your program.

The program is saved in a folder, which has a subfolder called "info."

In the info folder is a text file called "bikes. txt."

Which line of code will open bikes. txt?

results = open("info/bikes. txt","r")

results = open("bikes. txt","r")

results = open("info/bikes. txt","w")

results = open("bikes. txt","w")

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)?