What are the OS Management Activities for managing the file system? Select the correct answer.

A$.1.$ Creating and deleting files and directories $2.$ Primitives to manipulate files and directories $3.$ Mapping files onto secondary storage

B$.1.$ Creating and deleting files and directories $2.$ Primitives to manipulate files and directories $3.$ Mapping files onto secondary storage $4.$ Backup files onto secondary $($non$-$volatile$)$ storage media

C$.1.$ Creating and deleting files and directories $2.$ Mapping files onto secondary storage $3.$ Backup files onto stable $($non$-$volatile$)$ storage media

D$.1.$ Creating files and directories $2.$ Primitives to manipulate files and directories $3.$ Mapping files onto secondary storage $4.$ Backup files onto secondary $($non$-$volatile$)$ storage media