Which symbol is listed for the open-back unrounded vowel as described?

• A. /u:/
• B. /ɑ:/
• C. /v/
• D. /f/

Answer: (B)

Open-back unrounded vowels are produced with the tongue low and pulled back in the mouth, and the lips are unrounded. In IPA, that sound is represented by /ɑ/; when the vowel is described as long, it’s written as /ɑː/ (often shown as /ɑ:/ in some transcriptions). Among the given symbols, /ɑ:/ is the one that matches an open-back unrounded vowel. The other symbols either represent a high back rounded vowel (/u:/) or are consonants (/v/, /f/), which don’t describe a vowel at all.