Fruits stored in a cold chamber exhibit longer storage life because

The correct answer is C. Fruits are living tissue, and they keep respiring after harvest, burning stored sugars and acids and releasing heat and water. Low temperature slows the enzymatic reactions behind respiration, so reserves last longer, ripening and senescence are delayed, and shrivelling is reduced. This is the basic principle of cold storage.

• A is wrong. Light is not what drives post-harvest deterioration. Cold chambers are dark, but darkness is not the cause of longer life.
• B is wrong. Cold chambers do not raise CO2. Elevated CO2 is a separate method, controlled atmosphere storage, and it is not the basis of ordinary cold storage.
• D is wrong. Humidity is kept high mainly to prevent dehydration. It does not extend life by itself, and excess moisture favours moulds and rot.

On the Mains side, post-harvest losses of perishables are a recurring theme. It links to the cold chain, the role of NHM and PMKSY in creating storage infrastructure, and farmer income.

Trap: Aspirants pick humidity or CO2 because they sound like storage conditions. The core effect of a cold chamber is temperature-driven slowing of respiration.