Concept:The sound made by the letters “er” in “fern” is the long vowel /ɜː/.
Explanation:The word “fern” is pronounced /fɜːn/.
Its underlined letters “er” produce the same vowel sound as in “bird” or “hurt”.
Check each option:
“merge” is pronounced /mɜːdʒ/ — this has the same vowel /ɜː/.
“beryl” has a short /e/ sound, not /ɜː/.
“heart” is pronounced /hɑːt/, with the vowel /ɑː/.
“eureka” begins with /jʊə/ or /juː/, so it does not match.
Therefore, “merge” shares the same vowel sound as “fern”.
Answer:A. merge