Topic: Subject Verb Agreement,

Best Answer Explained in Below-:

The correct answer to the sentence "Either of the ____ to blame for the damage" is actually **C) two girls are**, not **D) two girls is**. The confusion arises from understanding the grammatical structure regarding the use of "either" and subject-verb agreement.

When "either" is used, it refers to one of the two options in a pair. Therefore, when completing the sentence, it's important to know that "either" implies a singular subject but can be grouped with plural nouns if those nouns refer to a collective idea of singular units.

In this context, the phrase "Either of the two girls" would still lead to a plural subject ("the two girls"), demanding the plural verb "are." Thus, the correct completion of that sentence is "Either of the two girls **is** to blame for the damage," showing that we refer to one girl out of the two as potentially responsible.

Completing the sentence with "two girls are" would also make sense, but it would change the meaning slightly, stating that both girls are collectively being blamed.

In summary, the correct answer in the multiple-choice format must acknowledge the need for verb agreement with subject - and simplified to "Either of the two girls **is** to blame" directly addresses the structure being questioned. However, to clarify, **C) two girls are** is also grammatically possible depending on context.