Here are the words that differ from the others in the position of primary stress for each question:

1. **C. unusual** (Stress is on the second syllable, while the others are on the second syllable as well but in a different pattern.)

2. **B. detective** (Stress is on the second syllable, while the stress in the other words is on the first syllable.)

3. **C. crowded** (Stress is on the first syllable, while the stress is on the second syllable in the others.)

4. **C. always** (Stress is on the first syllable, or often perceived differently compared to the others which have more straightforward stress.)

5. **A. invite** (Stress is on the second syllable, while the others are mostly on the first or follow simpler patterns.)

6. **A. comer** (Stress is on the first syllable, while the stress patterns of the others differ.)

7. **C. karate** (Stress is on the second syllable, while the others have first syllable stress.)

8. **B. programme** (If considering British pronunciation, often the stress is differently placed compared to the others.)

9. **A. toothache** (Usually perceived with first syllable stress, while the others generally have more common stress patterns.)

10. **D. performance** (D. follows a different stress pattern compared to the others which can be determined within the context.)

Please verify the stress patterns as pronunciation and regional differences may apply!