Final answer:
An irregular plural noun is a noun that does not follow the typical rules for pluralization in English. The word 'nobody' is an example of an irregular plural noun.
Step-by-step explanation:
An irregular plural noun is a noun that does not follow the typical rules for pluralization in English. Instead of adding -s or -es to the singular form, these nouns have unique ways of becoming plural. In the given options, the word 'nobody' is an irregular plural noun because it does not have a plural form and remains the same in both singular and plural.
Learn more about Irregular plural nouns