Correct Answer: C
Explanation:
The original sentence contains an error in noun-pronoun agreement: the plural possessive pronoun "their" is used to refer to "the worker," a singular noun. We need to use a singular possessive pronoun to refer to a singular noun, and our choices in this case are "his," "her," and "its." One doesn't use "its" to refer to people, and while "the worker" is not a gendered noun, we can tell that the worker being described in the sentence is male because of the use of the possessive pronoun "his" in the phrases "his lost green helmet" and "made his way home happily." For the sentence to be correct, we need to replace "their" with "his," so the correct answer is "Just as he finished work for the day, the worker found his lost green helmet and made his way home happily."