**Final Answer:**
The character von Rumpel is depicted as an individual consumed by the quest for a rare and precious jewel called the Sea of Flames. There for the correct option is a) Expensive and rare materials
**Explanation:**
In Anthony Doerr's novel "All the Light We Cannot See," von Rumpel, a character obsessed with finding a rare jewel called the Sea of Flames, utilizes expensive and rare materials in his work. His pursuit of the gemstone leads him to employ various resources and techniques associated with precious and scarce materials to track down the elusive stone. Throughout the narrative, von Rumpel's focus remains on obtaining this highly sought-after and valuable jewel, indicating his reliance on expensive and rare materials to achieve his objectives.
The Sea of Flames is portrayed as a legendary diamond with supposed mystical powers, making it a rare and precious item sought after by many. Von Rumpel's obsession drives him to use his expertise and resources, likely including rare elements and valuable materials, to locate and possess this extraordinary gemstone. The text emphasizes his relentless pursuit, indicating his reliance on high-value, exclusive materials to accomplish his goals.
In summary, von Rumpel's work primarily involves the pursuit of rare and expensive materials, particularly focusing on obtaining the Sea of Flames, a highly coveted jewel. His relentless pursuit underscores the significance of costly and exclusive resources in his endeavors throughout the novel.
There for the correct option is a) Expensive and rare materials