What is the correct pronoun for the sentence: "The southernmost state of the country has not updated (its, their) rules and regulations about smoking in public?"

In this sentence, the correct pronoun is "its." The subject of the sentence, "the southernmost state of the country," is a singular noun. When referring to singular nouns, particularly those that are inanimate or represent entities like states, the possessive pronoun "its" is appropriate to indicate ownership or association.

Using "its" signifies that the rules and regulations mentioned belong to the singular entity of the state. The other pronouns do not fit the context of the sentence. "Their" implies a plural subject and is not suitable here since "the southernmost state" is singular. "His" and "her" are used to denote possession for individuals and are not applicable for inanimate objects or places. Thus, "its" correctly maintains the singular form while conveying the intended meaning.