Assertion (a) :The main constituent of the liquefied petroleum gas is methane.
Reason (R): Methane can be used directly for burning in homes and factories where it can be supplied through pipelines.

Correct Option (d)

Assertion (A) states that the main constituent of liquefied petroleum gas (LPG) is methane. This statement is incorrect. LPG is primarily a mixture of propane (C₃H₈) and butane (C₄H₁₀), stored under pressure in liquid form. Methane (CH₄) is the primary component of natural gas, not LPG.

Reason (R) states that methane can be used directly for burning in homes and factories where it can be supplied through pipelines. This statement is correct. Methane, as the main component of natural gas, is widely used as a domestic and industrial fuel. It is efficiently supplied to consumers via extensive pipeline networks, offering a clean and convenient energy source.

Since Assertion (A) is false and Reason (R) is true, option (d) is the correct choice.

Incorrect Options

Options (a) and (b) are incorrect because Assertion (A) is factually false, as methane is not the main constituent of LPG.

Option (c) is incorrect because Reason (R) is factually true, as methane is indeed supplied through pipelines for burning in homes and factories.