A. generation - /ˌdʒɛnəˈreɪʃən/
B. goose - /ɡuːs/
C. ginger - /ˈdʒɪndʒər/
D. engineer - /ˌɛndʒɪˈnɪər/

The different sound is in B. goose. The other words have the /dʒ/ sound in the underlined part, while "goose" has the /uː/ sound.

A. question - /ˈkwɛsʧən/
B. mosquito - /məˈskiːtoʊ/
C. mosque - /mɒsk/
D. unique - /juːˈniːk/

The different sound is in C. mosque. The other words have the /kw/ or /k/ sound, while "mosque" has the /m/ sound.

A. mechanic - /mɪˈkænɪk/
B. stomachache - /ˈstʌməkˌeɪk/
C. Christmas - /ˈkrɪs·məs/
D. chance - /tʃæns/

The different sound is in D. chance. The other words have the /k/ or /s/ sound, while "chance" has the /tʃ/ sound.

A. giggle - /ˈɡɪɡl/
B. gone - /ɡɒn/
C. engine - /ˈɛn.dʒɪn/
D. forget - /fɔːˈɡɛt/

The different sound is in B. gone. The other words have the /ɡ/ sound in the underlined part, while "gone" has the /ɒ/ sound.

A. complete - /kəmˈpliːt/
B. compass - /ˈkʌmpəs/
C. concert - /ˈkɒnsɜːt/
D. century - /ˈsɛn.tʃər.i/