The ancient ruins might have been destroyed during the biggest earthquake of the century.a.SVb.SVOc.SVAd.SVC

To analyze the sentence, we can break it down based on its structure as follows:

1. Subject and Verb Identification

• The subject of the sentence is "The ancient ruins."
• The verb is "might have been destroyed."

2. Complement Identification

• The sentence does not contain a direct object since "destroyed" is a passive verb in this context.
• There is a prepositional phrase "during the biggest earthquake of the century." This adds information about when the destruction might have occurred but focuses on the action rather than providing a direct object.

3. Sentence Structure Classification

Based on the above analysis:

• a. SV (Subject + Verb) would require a simple subject and verb without additional information, which is not the case here.
• b. SVO (Subject + Verb + Object) is not applicable since there's no direct object.
• c. SVA (Subject + Verb + Adverbial) applies because the prepositional phrase acts as an adverbial modifying the verb.
• d. SVC (Subject + Verb + Complement) is also inappropriate as there isn’t a complement.

Final Answer

The correct structure is c. SVA (Subject + Verb + Adverbial).