Identify the function of the phrase contained in the following sentence. her main concern was wearing a diamond necklace. subject direct object predicate noun adverb adjective object of a preposition

The function of the phrase contained in the sentence is letter C) predicate noun.

Explanation:

A predicate noun or predicate nominative is a noun or noun phrase that comes after a liking verb (such as "to be") and has the purpose of providing further information about the subject of the sentence. Predicate nouns do not follow action verbs, since they don't express actions, but states of being.

In the sentence we are analyzing here, "Her main concern was wearing a diamond necklace," "wearing a diamond necklace" is a gerund phrase. Gerund phrases are constituted by a gerund and its complements or modifiers. Gerunds and gerund phrases function as nouns in a sentence, which means they can be subjects, objects, or predicate nouns. In this case, the gerund phrase "wearing a diamond necklace" is a predicate noun. It follows  the linking verb "was" and offers further information about the subject "her main concern".