Final answer:
Zirconia is the dental crown material that can undergo transformation toughening, a process that increases fracture toughness by a crystalline phase transformation in the presence of stress, beneficial for making durable dental crowns.
Step-by-step explanation:
The crown material that can undergo transformation toughening is B) Zirconia. Transformation toughening is a mechanism that increases the fracture toughness of a material. It involves the transformation of a material's crystalline phase in the presence of stress, which can help to blunt a crack and prevent its propagation. Zirconia, or zirconium dioxide, is known for this property, which makes it a highly valuable material in dentistry for constructing durable dental crowns.