Please be 100% sure

Which of the following statements is true? You may select more than one. Question 12 options:

A) RAM disks usually improve file read and write performance when used with modern operating systems that employ virtual memory.

B) File systems control how information is stored and retrieved. Hierarchical file systems organize information into multiple named files and multiple named directories so that each directory may contain many files and other directories. Hierarchical file systems impose the restriction that each file is identified by a exactly one unique path composed of a sequence of one or more directory names followed by the file name.

C) The term, "File system", refers to the abstract data structures used to define files but not the actual software or firmware components that implement the abstract ideas.

D) File systems manage access to both the content of files (data) and information about files (metadata).