Option 1 states that both the assertion (A) and the reason (R) are true, and that the reason is the correct explanation of the assertion. Graphite being used as a lubricant in the machine industry is indeed true. Graphite has a layered structure with weak bonds between the layers, allowing them to slide past each other easily. This property makes graphite excellent for reducing friction between surfaces, hence its use as a lubricant. The reason given for this in option 1 is that graphite is soft and a good conductor of heat, which is also true.

Option 2 states that both the assertion and the reason are true, but the reason is not the correct explanation of the assertion. This is the correct answer. While it is true that graphite is soft and a good conductor of heat, these properties alone do not directly explain why graphite is used as a lubricant in the machine industry. The key factor is the layered structure of graphite, which enables easy sliding between layers and reduces friction.

Option 3 is incorrect because the assertion is true. Option 4 is also incorrect because the reason is true.

In conclusion, Option 2 accurately represents that both the assertion and the reason are true, but the reason is not the correct explanation of the assertion