In the given sentence, the incorrect word is "Otheir." The correct word should be "their" without the additional letter "O" at the beginning. Here's a breakdown to explain the error:
1. "everybody's" - This word is correctly used in the sentence to indicate possession, showing that something belongs to everybody.
2. "their" - This word is also correct in the sentence as it is a possessive pronoun indicating possession by more than one person.
3. "Otheir" - This word is incorrect as it contains an extra letter "O" at the beginning that does not belong there. The correct form should be "their."
4. "they're" - This word is a contraction of "they are," which doesn't fit the context of the sentence. The sentence is talking about possession, so "they're" would not be the appropriate word here.
Therefore, the incorrect word in the sentence is "Otheir," and it should be replaced with "their" to make the sentence grammatically correct.
