Final answer:
In phonetics, vowels are categorized based on the lip position as either rounded or unrounded. 'Rounded lips' involve a circular shape, whereas 'unrounded lips' are produced without rounding. The terms 'spread lips' and 'compressed lips' are not standard for vowels. Thus (option a & b) is right answer.
Step-by-step explanation:
When categorizing vowels based on the position of the lips, we look at whether the lips are rounded or not. There are generally two categories:
- Vowels with rounded lips: These vowels require the lips to form a circular shape. Examples of such vowels in English include the sounds represented by 'o' in 'note' or 'u' in 'rude'.
- Vowels with unrounded lips: These vowels are produced without rounding the lips. Examples in English include the sounds represented by 'a' in 'cat' or 'i' in 'sit'.
However, the categories "vowels with spread lips" and "vowels with compressed lips" are not standard terms in phonetics. Instead, you may encounter terms like "spread" to describe a feature of certain consonants, or "compressed" to describe a narrow lip posture, but these typically do not apply to vowel classification. Thus (option a & b) is right answer.