Correct option is B
Mar-quenching, also known as stepped quenching, is the process that permits the transformation of austenite to martensite throughout the cross-section of a component without cracking or distortion. In this process, the component is quenched rapidly to a temperature just above the martensite start temperature, held there to allow temperature equalization, and then cooled in air to complete the martensite transformation. This reduces thermal stresses, minimizing the risk of cracking and distortion, and results in a more uniform microstructure.
