Final answer:
The plural of 'babysitter' is 'babysitters', which is simply formed by adding an '-s' to the end of the word. option 1 is correct.
Step-by-step explanation:
The plural of babysitter is babysitters. When forming the plural of most nouns in English, we simply add an -s or -es at the end of the word. Therefore, the correct option is 1) babysitters. Remember, we do not change the base part of the word when making it plural; the letters -ies would only be used if the singular noun ended with a -y preceded by a consonant and needed to be changed to -ies, which is not the case with babysitter.