Final answer:
In the given sentence, 'smooth as glass' functions as a delayed adjective, modifying 'an oval of ice.' The correct answer is d) delayed adjective. 'When' serves as an adverb referring to time.
Step-by-step explanation:
The underlined words in the sentence "An oval of ice, smooth as glass, awaited the skaters." function as an adjective modifying the noun 'oval.' It is a delayed adjective, which means it comes after the noun it describes, and offers additional information about the noun's quality or characteristic. In this case, 'smooth as glass' describes the 'oval of ice.' Considering the options provided, the correct answer is d) delayed adjective.
To balance the sentence, an adjective or noun is typically needed to complete the subject. An adverb is a word that modifies verbs, adjectives, or other adverbs and often refers to time, place, reason, or manner. 'When' is considered an adverb because it refers to time and would usually begin an adverbial clause, indicating when the action of the clause is occurring.