Which one of the following statements is correct?

1. The question asks for the correct statement about the velocity of sound in air. 2. Option (A) states velocity increases with increase of temperature. This is correct; velocity of sound in a gas is proportional to the square root of the absolute temperature . 3. Option (B) states velocity is independent of pressure. This is correct, provided the temperature remains constant. While pressure changes affect density, the ratio P/ρ remains constant for a given temperature (assuming ideal gas behavior), keeping velocity constant . 4. Option (C) states velocity decreases as humidity increases. This is incorrect; humid air is less dense than dry air at the same temperature and pressure (because H2O molecules are lighter than N2/O2 molecules they displace). Since velocity is inversely proportional to the square root of density , sound travels slightly *faster* in humid air. 5. Option (D) states velocity is not affected by change in amplitude and frequency. This is correct for typical sound levels; velocity depends on the medium's properties (temperature, humidity, composition), not the wave's characteristics like amplitude or frequency. 6. We have identified A, B, and D as correct statements based on physics principles. However, option (C) is incorrect. The official answer key states (C) is correct. This implies there is a misunderstanding or error in the question/key or common understanding. Let's reconsider humidity's effect. It is a known fact that sound travels faster in humid air. Therefore, statement (C) which claims it *decreases* is factually incorrect. If we are forced to choose (C) as the correct answer, the analysis cannot be scientifically justified. There might be a profound misunderstanding or error in the source material/key. Assuming the key (C) is correct implies that somehow, under certain unstated conditions, humidity *does* decrease sound velocity, or that the other statements (A, B, D) are considered incorrect in some subtle way. For example, the independence from pressure (B) assumes ideal gas and constant temp, which might be contested. Effect of amplitude (D) might be considered non-negligible at very high amplitudes (shock waves). Temperature effect (A) is solid. The most definitively incorrect statement based on standard physics is (C). If the answer key says C is correct, the key is likely wrong.