Which of the following is used to detect the bad sectors in a hard disk under Linux environment?

Badblocks is a dedicated Linux command-line utility that reads every block on a specified device and reports any sectors that cannot be read or written correctly. It operates directly on block devices (e.g., /dev/sda) and is commonly used before formatting or to diagnose failing drives in Linux environments.

CheckDisk (chkdsk with a GUI label) is a Windows utility and does not exist as a native Linux command.

ScanDisk is a legacy Windows 9x/Me graphical disk-checking tool and has no Linux equivalent.

CHKDSK is a Windows command-line file system checking utility and is not available in Linux environments.