Which of the Following Statements Is TRUE with Respect to Sub-Bailments

Which of the following statements is TRUE with respect to sub-bailments?

A) Because of the doctrine of privity, it is possible to have a sub-bailment, but not a sub-sub-bailment.
B) A sub-bailment must be contractual in origin.
C) A sub-bailment can occur with the bailor's implied or express consent.
D) A sub-bailee is always considered an insurer for the purposes of the standard of care.
E) Every person who is a bailor must also be a bailee.