Step 1: Understanding the Mond process.
The Mond process is a method used to purify nickel by converting it into a volatile carbonyl complex and then decomposing it to obtain pure nickel. This process is specifically used for nickel.
Step 2: Analyzing the options. (A) Zn: Zinc is not purified by the Mond process. (B) Si: Silicon is not refined by the Mond process. (C) Ni: Correct — Nickel is refined by the Mond process. (D) Zr: Zirconium is not refined by the Mond process.
Step 3: Conclusion.
The correct answer is (C) Ni, as nickel is refined using the Mond process.