Here are the answers to your questions based on the underlined parts and stress differences:

1. **A.** "antibiotic" - differs in pronunciation from the other three.
2. **B.** "spread" - differs in pronunciation from the other three.
3. **C.** "illness" - differs in pronunciation from the other three.

For the stress questions:

4. **B.** "poisoning" - differs in stress from the other three.
5. **A.** "diameter" - differs in stress from the other three.

For the additional questions:

6. **A.** "story" - differs in a common context from the other three (focus on different aspects).
7. **D.** "unhealthy" - is the opposite of the idea presented in the sentence.

Feel free to ask if you need further assistance!