Answer:
Step-by-step explanation:
Going through the options:
O Passwords typically are not case-sensitive.
Passwords are typically case-sensitive.
O Using a document to store the password is not allowed.
It is not recommended but definitely allowed to store passwords in document.
O If a user forgets the password, it cannot be recovered.
Lost password cannot be recovered easily but not impossible.
The only choice left is
O There is a private password for the user and a public one for the viewer.
It describes a set of public and private key password used to allow sharing of encrypted files between user and viewers.
So the only answer left which is correct:
O If a user forgets the password, it cannot be recovered.