To answer this question, you need to understand the concept of adulteration of petrol and the properties of different fuels.
Option A) Diesel - This option is incorrect because diesel is not commonly used as an adulterant for petrol. Diesel has a different composition and properties compared to petrol, and it is not easily miscible with petrol.
Option B) Kerosene - This option is incorrect because kerosene is also not commonly used as an adulterant for petrol. Like diesel, kerosene has different properties and is not easily miscible with petrol.
Option C) Naphtha - This option is correct because naphtha is a common adulterant of petrol. Naphtha is a much cheaper and lighter fuel extracted from crude oil. It has properties that make it easily miscible with petrol, allowing it to escape detection. However, the adulteration of petrol with naphtha can cause damage to the vehicle engine and lead to high emission levels.
Option D) Mobile oil - This option is incorrect because mobile oil is not commonly used as an adulterant for petrol. Mobile oil is a lubricating oil used for engines and machinery, and it is not easily miscible with petrol.
The correct answer is C) Naphtha. This option is correct because naphtha is a common adulterant of petrol that easily escapes detection due to its properties and can cause damage to the vehicle engine.