John's watch is made of GOLD.

Analyze the question: Emphatic stress is placed on the word that carries the new or contrasting information. The capitalized word GOLD is the focus, so the sentence must be the answer to a question that asks about the material the watch is made of.

Concept: In these questions, the stressed word is the answer to the question, or it corrects a wrong idea in the question. Ask yourself: "Which question would make GOLD the new information?"

Step-by-step check:

• A. Whose watch is made of gold? The new information would be "John's", so the stress would fall on JOHN'S. This is not a match.
• B. What is made of gold? The new information would be "watch", so the stress would fall on WATCH. This is not a match.
• C. Is John's watch made of silver? This asks about the material. The reply "No, John's watch is made of GOLD" corrects "silver" with "gold", so the stress falls on GOLD. This is a match.
• D. Is John's necklace made of gold? The wrong idea is "necklace", so the stress would fall on WATCH. This is not a match.

Answer: The correct option is C.

Tip: Find the word in the question that the capitalized word replaces or corrects. Here, GOLD replaces "silver". In the other options, the words being questioned (whose, what, necklace) are not the material, so the stress would fall elsewhere.