Which noun refers to the process of changing something completely?

• A. Conversion
• B. Transformation
• C. Replacement
• D. Extension

Answer: (B)

The idea being tested is that transformation denotes a thorough, fundamental change in form, appearance, or nature. When something undergoes a transformation, it becomes something quite different overall, often across many aspects of what it is.

This makes it the best choice because it explicitly captures a complete or major change. Replacement means substituting one thing for another, which isn’t about the process of changing the same thing itself. Conversion can involve change, but it’s not always a total or fundamental overhaul and is sometimes about changing function or state. Extension is about lengthening or broadening rather than changing the core character.