Concept:The underlined letter 'h' in 'hack' represents the consonant sound /h/.Explanation:The word 'hack' is pronounced /hæk/, so we need a word that also contains the /h/ sound.A. behaviour /bɪˈheɪvjə/ contains /h/.B. schedule /ˈʃedjuːl/ has no /h/ sound.C. exhibit /ig’zibit/ has no /h/ sound.D. honourable /ˈɒnərəbl/ has a silent 'h', so it is not pronounced.Thus, the word with the same consonant sound as 'h' in 'hack' is behaviour.Answer:A. behaviour