Final answer:
The element Roentgenium is named after Wilhelm Roentgen, who discovered x-rays. The correct answer to the student's question is option C. Roentgenium.
Step-by-step explanation:
The chemical element named after Wilhelm Roentgen, the physicist who discovered x-rays, is Roentgenium. Roentgen's use of cathode ray tubes led to the remarkable discovery of x-rays when he observed a barium platinocyanide screen fluoresce. After experimenting with various substances, he realized that the rays penetrated various objects and left an image on photographic film. His discovery significantly contributed to our understanding of atomic structure and opened doors for further research in radioactivity by scientists like Henri Becquerel and the Curies. Roentgen was awarded the Nobel Prize in Physics in 1901 for his discovery of x-rays. Given this historical context, the correct answer to the question is C. Roentgenium.