Which of the Following Is a True Statement Regarding Data

Which of the following is a true statement regarding data flows?

A) A data flow to a data store means retrieve or use.
B) A data flow from a data store means update.
C) A data flow may have double-ended arrows.
D) A data flow represents data at rest.
E) A join in a data flow means that exactly the same data come from any of two or more different processes, data stores, or sources/sinks to a common location.