Match common DOS commands with their primary functions: (A) ATTRIB, (B) SCANDISK, (C) MOVE, (D) TREE — with: (1) displays all directories and subdirectories, (2) moves files to another directory, (3) checks the status of the disk, (4) hides or changes attributes of a file.

Introduction / Context:
DOS utilities provide file, directory, and disk-maintenance operations. Knowing what each command does is essential for legacy systems and foundational operating-system literacy.

Given Data / Assumptions:

• Commands: ATTRIB, SCANDISK, MOVE, TREE.
• Functions: list directory tree, move files, check disk status, set/hide attributes.

Concept / Approach:
Map each command to its main purpose from standard DOS help manuals: ATTRIB changes attributes; SCANDISK checks/repairs; MOVE relocates files; TREE displays directory hierarchy.

Step-by-Step Solution:

Verification / Alternative check:
Running 'command /?' or DOS manuals confirms each mapping (ATTRIB, SCANDISK, MOVE, TREE) with the listed functions.

Why Other Options Are Wrong:

• A-1, B-2, C-3, D-4: Swaps TREE with ATTRIB and misassigns others.
• A-3, B-4, C-2, D-1: Interchanges ATTRIB and SCANDISK purposes.
• A-2, B-3, C-4, D-1: Mixes up ATTRIB and MOVE.

Common Pitfalls:

• Assuming ATTRIB merely hides files; it can set multiple attributes (+R, +H, +S).
• Confusing SCANDISK with CHKDSK; both check disks, but SCANDISK (DOS 6.x) offered enhanced repair/reporting.

Final Answer:
A-4, B-3, C-2, D-1