C. watched

The "ed" ending in "watched" is pronounced /t/, while in "addicted," "complicated," and "provided," it is pronounced /ɪd/.

D. custom

The "u" in "custom" is pronounced /ʌ/, while in "communal," "useful," and "university," it is pronounced /juː/.

C. culture

The "u" in "culture" is pronounced /ʌ/, while in "understand," "destruction," and "communicate," it is pronounced /ə/ or /ʌ/.

D. chemistry

The "ch" in "chemistry" is pronounced /k/, while in "speech," "chatting," and "cheer," it is pronounced /ʧ/.

A. wave

The "a" in "wave" is pronounced /eɪ/, while in "landslide," "damage," and "natural," it is pronounced /æ/.

B. nonverbal

The "o" in "nonverbal" is pronounced /ɒ/, while in "conference," "social," and "body," it is pronounced /ə/.