Find the word whose underlined part differs from the other three in pronunciation

I. Find the word whose underlined part differs from the other three in pronunciation.
1.
A. study                            
B. sleep                                  
C. school                               
D. island
2.
A. improved                      
B. waited                               
C. collected                           
D. attended
3.
A. plane                             
B. camping                            
C. kayaking                           
D. rafting
4.
A. best                               
B. tent                                   
C. jacket                                
D. get