Select all that are true of the need for convenient and safe backup storage. $($Check all that are true.$)$

a$.$

The DBA should establish a policy for how long backups are stored and where.

b$.$

The storage locations of the backups should usually include sites both inside and outside the organization.

c$.$

Only the DBA should have access to the storage locations.

d$.$

It is highly desirable to produce multiple backups of the same data, and to store each backup copy in a different location.