Choose the word whose main stressed syllable is placed differently from that of the other in each group

Choose the word whose main stressed syllable is placed differently from that of the other in each group.
1. A. across B. behind C. around D. hardly
2. A. careful B. modern C. alive D. worried
3. A. signal B. police C. driver D. helmet
4. A. tricycle B. buffalo C. motorway D. appliance
5. A. obey B. listen C. whistle D. open
6. A. mistake B. second C. puzzle D. traffic
7. A. prepare B. prefer C. attend D. answer
8. A. police B. children C. teacher D. student
9. A. distance B. design C. driving D. station
10. A. happy B. alive C. busy D. early
11. A. horror B. cartoon C. action D. thriller
12. A. attack B. believe C. decide D. finish
13. A. combine B. confuse C.annoy D. listen
14. A. enjoy B. perform C. study D. direct
15. A. special B. lazy C. alone D. ugly