Choose the word Slaving the underlined part pronounced differently in each line

I. Choose the word Slaving the underlined part pronounced differently in each line. (2.5p)
1. A. bottle
B. born
C. box
D. chocolate
2. A. corner
B. forty
C. horse
D. collector
3. A. call
B. quality
C. want
D. wash
4. A. fall
B. ball
C. tall
D. watch
5. A. hot
B. lock
C. fold
D. job