The correct answer is option 2, which states that a person must be above the age of 14 to be employed in factories or mines.
Option 1, which states 12 years, is not correct because it is below the legal working age for these types of establishments.
Option 3, which states 18 years, is also not correct because it is above the minimum age requirement for employment in factories or mines.
Option 4, which states 20 years, is not correct because it is unnecessarily higher than the actual minimum age requirement.
Therefore, option 2 is the correct answer as it accurately represents the minimum age requirement for employment in factories or mines.