The correct answer is: D. both (b) and (c)
A master list of an indexed file is a list of all the keys in the file, along with the record number of each record that contains that key. The master list is sorted in ascending order by key, so that it can be used to quickly find the record number of a given key.
Option A is incorrect because the master list is not necessarily sorted in ascending order. It can be sorted in any order that is convenient for the application.
Option B is correct because the master list contains only a list of keys and record numbers. It does not contain any other information about the records, such as the data values or the record length.
Option C is correct because each record in the file has a number assigned to it. This number is used to identify the record in the master list.
Option E is incorrect because both options B and C are correct.