it looked just like the older (boy's, boys's) which one is the correct possessive noun in this sentence?

boy's

boy's

boys

In order to determine the correct possessive noun in this sentence, we need to understand the rules for forming possessive nouns. Generally, when making a singular noun possessive, we add an apostrophe followed by an "s" ('s). When making a plural noun possessive, we typically add only an apostrophe after the final "s" (').

Now, let's consider the options in your sentence:

1. "boy's"
2. "boys's"

Since we are talking about something that's owned by the older boys (plural), we should use the plural possessive form. Therefore, the correct possessive noun in this sentence is "boys'".

So, the correct sentence would be:
"It looked just like the older boys'."