The correct answer is:

A is false but R is true.

Assertion (A): The main constituent of Liquefied Petroleum Gas (LPG) is methane.

This statement is false. While methane is a component of natural gas, which is used as a fuel, it is not the main constituent of LPG. LPG is primarily composed of propane and butane, with smaller amounts of other hydrocarbons.

Reason (R): Methane can be used directly for burning in homes and factories where it can be supplied through pipelines.

This statement is true. Methane, which is the main component of natural gas, can indeed be used directly for burning in homes and factories. In areas where natural gas pipelines are available, methane can be supplied through these pipelines for various applications, including heating, cooking, and power generation.

Therefore, the correct answer is:

A is false but R is true. Methane is not the main constituent of LPG, but it can be used directly for burning in homes and factories where it can be supplied through pipelines.