The correct answer is D. cp, which is a core Linux command used to copy files and directories. File management in Linux is performed primarily through command-line utilities, and cp is one of the most fundamental commands for this purpose.

According to the Quentin Docter – CompTIA A+ Complete Study Guide, Linux administrators frequently use commands such as cp, mv, rm, and ls to manage files. The cp command allows users to copy files between directories or locations and supports options for recursive copying and permission preservation.

The Travis Everett & Andrew Hutz – All-in-One Exam Guide highlights that Linux file management commands differ significantly from Windows equivalents. While Windows uses robocopy and xcopy, Linux relies on simpler, built-in commands like cp.

The Mike Meyers / Mark Soper Lab Manual further explains that curl is used for transferring data over network protocols, not for managing local files. Commands such as robocopy and xcopy are Windows-specific and not available in standard Linux environments.

Because the question asks specifically about managing files in Linux, and cp is a native Linux file-management command, D is the correct answer.