What is a characteristic of the high unrounded vowel?

A high unrounded vowel is defined by a specific tongue position within the mouth and its articulatory characteristics. In this case, the tongue is positioned high and toward the front of the mouth, which is precisely why option C is the correct answer. The term "high" refers to the elevation of the tongue, and "unrounded" indicates that the lips are not rounded when producing the sound. This is typified by vowels such as the "i" in "see" or the "ee" in "meet," where the tongue is elevated and placed forward.

The other options reflect properties that do not accurately describe high unrounded vowels. For instance, stating that the tongue is low (the first option) contradicts the definition of a high vowel, and designating the vowel sound as nasal (the second option) does not hold true for all high vowels, as nasalization depends on specific phonetic contexts rather than being an intrinsic characteristic. Lastly, regarding voicing (the fourth option), while many high vowels are indeed voiced, not all vowel sounds are voiced, and thus this statement is too broad to define a high unrounded vowel specifically.