Final answer:
The three third person singular nominative pronouns are he, she, and it.
Step-by-step explanation:
The three words that may be used as third person singular nominative pronouns are he, she, and it. These pronouns are used to refer to a single person or thing when they are the subject of a sentence. For example, 'He is going to the store,' 'She is reading a book,' and 'It is raining outside.' These pronouns help us to avoid repeating the noun in a sentence and make our language more concise.