Which word correctly completes the sentence?

did you notice if headlights are on in the parking lot?

a.
someones'

b.
someone's

c.
someones's

The correct word that best completes the given sentence is option B. someone's. We used the word someone with the apostrophe s, because it is showing possession or ownership, which is "someone's headlights". So the complete sentence would be: Did you notice if someone's headlights are on in the parking lot?

Lorna would be the complete subject in this sentence.