A. .pptx
B. .potx
C. .xlsx
D. .docx

Explanation:

• Stores presentation templates.
• Contains predefined layouts and themes.
• Saves design time.
• Ensures consistency.
• Useful for branding.
• Commonly used in organizations.
• Easy to share.
• Supports professional presentations.
• Frequently used by designers.
• Important file format.