Which of the following is NOT a simple energy conservation measure in household and commercial sectors? 

Leaving liquids uncovered in a refrigerator increases humidity, reduces efficiency, and leads to higher energy consumption. Covering liquids helps maintain lower moisture levels and keeps the refrigerator running efficiently, reducing energy costs.

Thus, option 3 is the correct answer because it is NOT an energy conservation measure but rather an energy-wasting habit.

• Use electronic chokes and fan regulators: Energy-efficient option as electronic chokes reduce power losses and regulators control fan speed efficiently.
• Use proper quantity of water for cooking: Helps in reducing unnecessary energy consumption during heating.
• Uncover all liquids placed in refrigerators: Uncovered liquids increase moisture inside the fridge, making the compressor work harder, and leading to higher energy consumption.
• Do not overload the washing machine: Prevents excessive energy and water usage, ensuring optimal efficiency.