Which statement best describes the comparative advantages of crown-down instrumentation and step-back instrumentation?

• A. Crown-down reduces coronal debris and minimizes ledging; Step-back helps create apical size control.
• B. Crown-down is primarily for reducing apical transportation.
• C. Step-back eliminates the need for irrigation.
• D. Crown-down is only used for NiTi files.

Answer: (D)