Topic: Word Meaning, Subject: English Grammar (ইংরেজি গ্রামার)

Best Answer Explained in Below-:

"Absolute zero" refers to the theoretical point at which a system reaches its lowest possible energy state, meaning the complete absence of thermal energy. This point is defined as 0 Kelvin (K) in the Kelvin temperature scale, which corresponds to -273.15 degrees Celsius (°C) in the Celsius scale. At absolute zero, all molecular motion stops, and a substance exhibits minimum entropy, making it a fundamental concept in thermodynamics and physics.

The significance of -273°C is profound in scientific research, particularly in fields such as cryogenics and quantum mechanics, where the behavior of materials at extremely low temperatures is studied. Traditional thermometers cannot measure below 0°C, and the laws of physics, as we understand them, imply that reaching absolute zero is impossible due to the third law of thermodynamics, which states that an infinite amount of energy would be required to cool a system to this temperature.

Thus, option B) -273°C temperature is indeed the correct choice, as it encapsulates the concept of absolute zero, distinguishing it from the other options that do not relate to thermodynamic principles.