What is the range of tempering temperature (°C) for most of the materials ?

ANS:B - 200-300

The range of tempering temperature (°C) for most materials typically falls within the range of 200-300°C. Tempering is a heat treatment process applied to hardened steel or other materials to reduce brittleness, improve toughness, and adjust hardness. The tempering temperature is crucial as it determines the final mechanical properties of the material. In the range of 200-300°C, the material undergoes tempering, allowing for a balance between hardness and toughness. Therefore, the correct option is: 200-300°C.