When Fire-Resistance Treatments Are Applied to Wood Paneling Which of the Following

When Fire-resistance treatments are applied to wood paneling which of the following is the best method?

A) Applied to the surface to the entire surface is covered to avoid penetration of the core.
B) Applied to the secondary layer to allow the top finish to be painted if necessary.
C) Applied as a core layer so the surface can be finished to the desired effect.
D) Applied through impregnation of the cores and cross bands with waterborne salts.