Which steps are necessary when using the air-water syringe and suction during patient treatment?

• A. Use sterile or properly cleaned suction tips; dispose of single-use items; flush lines before and after use; clean and disinfect external surfaces; prevent cross-contamination and ensure proper reprocessing of reusable components.
• B. Use any disposable tip; reuse tips without cleaning.
• C. Never flush lines.
• D. Only clean external surfaces after use.

Answer: (D)