Which of the following phonemes is a voiceless alveolar fricative?

The phoneme that corresponds to a voiceless alveolar fricative is /s/. To understand why this is the correct choice, it's essential to break down the terms involved.

"Voiceless" refers to sounds produced without vibrating the vocal cords. In the case of /s/, when articulating this phoneme, the airflow is directed through a narrow constriction at the alveolar ridge (located just behind the upper front teeth), creating turbulence, which results in the fricative quality of the sound. The lack of vocal cord vibration during its production confirms that /s/ is indeed voiceless.

The term "alveolar" indicates the place of articulation. Sounds that are produced at the alveolar ridge are made with the tongue contacting this area, which is precisely what happens with /s/.

Finally, "fricative" describes the manner of articulation, where the airflow through a narrow channel creates friction. The production of /s/ involves the tongue raising close to the alveolar ridge while allowing air to pass through, creating the characteristic hissing sound of a fricative.

Other phonemes presented do not fit these criteria. For example, /b/ is a voiced bilabial stop, /k/ is