Given below are two statements, one is labelled asAssertion (A) :and the other as Reason (R).Assertion (A):CO₂, SO₂, and NO₂ gases get dissolved in rain water and produce acid rain.Reason (R):Atmospheric air is polluted due to high concentration of gases like carbon dioxide, sulphur dioxide and oxides of nitrogen.Select the correct answer from the codes given below:

1. A

   Both (A) and (R) are true and (R) is the correct explanation of (A).

   Both (A) and (R) are true and (R) is the correct explanation of (A). This option correctly establishes that the high atmospheric concentration of pollutant gases like carbon dioxide, sulphur dioxide, and oxides of nitrogen directly leads to their dissolution in rainwater to cause acid rain, making it the correct choice.

2. B

   (A) is false, but (R) is true.

   (A) is false, but (R) is true. This option incorrectly claims that the assertion regarding acid rain formation is false.

3. C

   Both (A) and (R) are true, but (R) is not the correct explanation of (A).

   Both (A) and (R) are true, but (R) is not the correct explanation of (A). This option wrongly denies the causal link between atmospheric pollution by these specific gases and the resulting acid precipitation.

4. D

   (A) is true, but (R) is false.

   (A) is true, but (R) is false. This option erroneously suggests that the reason concerning high concentrations of pollutant gases in the atmosphere is false.

Summary. Official key is (a) Both (A) and (R) are true and (R) is the correct explanation of (A). The assertion correctly states that gases such as carbon dioxide, sulphur dioxide, and nitrogen oxides dissolve in rainwater to produce acid rain. The reason accurately explains that atmospheric air becomes polluted due to the high concentration of these exact gases. Since the pollution of air by these emissions is the direct cause of acid rain, both statements are factually correct and logically linked. Therefore, option (a) is the only valid and complete explanation among the given choices.