Mario was surprised that the box that was supposed to tell him how many words he used in his document did not appear after the spelling and grammar check of his document was complete. Which step did Mario forget to do in Word’s Options dialog box?

Click the Display tab.
Click the Custom Dictionaries button.
Click the Grammar checking option.
Click the Show the readability statistics option.

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)?