Which of the following is/are correct regarding linear oxidation law?

• A. Weight gain per unit area of the metal is directly proportional to the exposure time
• B. It is a characteristic of porous or cracked scale
• C. Sodium is an example that follows linear oxidation law
• D. Weight gain per unit area of metal is directly proportional to exposure time, it is characteristic of porous or cracked scale and sodium follows linear oxidation law