You have been asked to recommend the file type to be used in a retail OLTP application. The file
will contain the customer’s credit card information:
credit card number
name of the customer
credit limit and account balance
The file will be accessed when the customer purchases products with their store credit card.
Select the file type best suited to this transaction.

A.
Unstructured

B.
Entry-Sequenced

C.
Relative

D.
Key-Sequenced