Fruits stored in a cold chamber exhibit longer storage life, because

The correct answer is C) Rate of respiration is decreased. Fruit is living tissue even after harvest, and it keeps respiring by breaking down stored sugars and organic acids. Lower temperature slows the enzyme-driven reactions behind this, so respiration falls, ripening and softening are delayed, and senescence sets in later. This is the Q10 principle of postharvest physiology: a fall of about 10 degree C roughly halves or more the respiration rate.

• A: Cold chambers are dark, but darkness is not the mechanism. Sunlight exposure is not what limits storage life.
• B: Raised CO2 is a controlled-atmosphere technique, which is a separate method and not the reason a cold chamber works.
• D: Cold rooms are kept humid (around 85 to 95 percent) to reduce moisture loss and shrinkage. Humidity protects texture but does not slow metabolism.

This links to post-harvest loss reduction, cold chain infrastructure under the Mission for Integrated Development of Horticulture, and the Mains theme of farmer income and food wastage.

Trap: Many candidates pick D because cold stores feel humid. Humidity controls water loss; respiration control is the real reason for longer life.