Concept:The underlined vowel sound in the given word is the long open-mid central sound /ε:/.Explanation:The word burn is pronounced as /b3:n/.The letters ur together produce the vowel sound /3:/.Now check the vowel sounds in the options.A. barn is pronounced /ba:n/ — vowel sound /a:/.B. owl is pronounced /aυl/ — diphthong /au/.C. girl is pronounced /g3:l/ — vowel sound /ε:/.D. pus is pronounced /p∧s/ — vowel sound /∧/.Only option C has the same vowel sound /3:/ as the underlined letters in burn.Answer:C. girl