Which of the following is true of high-level offline storefronts?

Which of the following is true of high-level offline storefronts?

A.
They use only proprietary encryption and data-formatting standards.

B.
They are not designed to support business-to-business (B2B) needs.

C.
They require the site to be taken offline whenever a change is made.

D.
They require the greatest amount of expertise to use properly.