Correct option is B
Before brazing, it is crucial to properly clean the steel surface to remove oxides, dirt, oil, and other contaminants that can interfere with the bonding process. Emery cloth is a commonly used abrasive material for this purpose because it consists of fine particles of emery (a natural abrasive) bonded to a flexible backing, allowing effective cleaning of metal surfaces.
· Wet and dry silicon carbide paper is used primarily for fine finishing rather than aggressive cleaning before brazing.
· Wire tools, such as wire brushes, can remove loose debris but may not be effective in eliminating surface oxides.
· Aluminium oxide powder is used in blasting or polishing but is not commonly employed for manual pre-brazing cleaning.
