Which term describes a sound produced by closing both lips and releasing air, as in /p/ or /b/?

• A. Bilabial
• B. Alveolar
• C. Labiodental
• D. Palatal

Answer: (A)

This is about the place of articulation—the sound is made with both lips coming together and then releasing air. That description identifies bilabial consonants, and /p/ and /b/ are classic examples of bilabial stops (one voiceless, one voiced). The other terms refer to different articulatory points: alveolar involves the tongue and the ridge behind the teeth; labiodental uses the lower lip against the upper teeth; palatal involves the body of the tongue against the hard palate. So bilabial is the best fit for the described production.