The correct option is option 1: Both A and R are true and R is the correct explanation of A.

Explanation:

Greenhouse effect refers to the process by which certain gases in the Earth`s atmosphere trap heat, leading to the warming of the Earth`s surface. In this process, the thick carbon dioxide layer allows sunlight to filter through, just like glass panels of a greenhouse or glass windows of a motor car. This is because carbon dioxide and other greenhouse gases are transparent to visible light.

However, when sunlight reaches the Earth`s surface and is absorbed, it is re-radiated as heat in the form of infrared radiation. The thick carbon dioxide layer prevents this heat from being re-radiated into outer space, thus trapping it and contributing to the warming of the Earth`s surface. This is similar to how the glass panels of a greenhouse prevent heat from escaping, resulting in a warmer interior temperature.

In conclusion, both statement A and statement R are true. The thick carbon dioxide layer in the greenhouse effect allows sunlight to filter through but prevents heat from being re-radiated in outer space, just like the glass panels of a greenhouse or glass windows of a motor car.