Mark the letter A, B, C, or D to indicate the word that differs from the other three in the position of the primary stress in each of the following questions. 

Kiến thức: Trọng âm 

Giải thích: 

A. private /ˈpraɪvət/ 

B. protect /prəˈtekt/ 

C. reform /rɪˈfɔːm/ 

D. regard /rɪˈɡɑːd/