Which of the Following Is True Concerning In-Office Fluoride Application

Which of the following is true concerning in-office fluoride application?

A) The most commonly used fluorides come in the form of topical gels or foams that are applied for 1 minute in disposable trays.
B) A 1-minute application is recommended by the ADA.
C) The 1-minute application delivers approximately 25% of the fluoride that a 4-minute application delivers.
D) When used 1 to 2 times a year, topical fluoride treatments have been shown to produce 20% to 26% caries reduction.