Answer to Question 1
A B-tree is a multilevel index that allows both sequential and direct processing of data records. The B-tree index is composed of two parts: (1 ) a sequence set, which is an index containing an entry for every record in the file, and (2 ) an index set, which is an index pointing to groups of entries in the sequence set index. The index set provides rapid direct access to records in the file, and it is what makes a B-tree unique.
Answer to Question 2
D