Refer to the following extract from a requirements document for an online book store:
Users need not be registered with the store to be able to search for a particular book or browse

through the store. They can also add items to the shopping cart. When they wish to check-out the
shopping cart, the application must verify if they are already registered. If so, they should be
allowed to login and continue with the check-out. If they have already purchased in the store they
should be given a default choice of shipping address. Unregistered users should be given a choice
to register with the store or continue shopping.
Which of the following business rules can be extracted from the above requirements?

A.
Users must be registered to be able to add items to their shopping cart.

B.
Users must be registered to be able to search for a book.

C.
All registered users should be given a default choice of shipping address.

D.
Users need to be authenticated before they can make a purchase.

E.
Users must be registered before they can make a purchase.