In which sentence is the apostrophe correctly used to indicate possession?

✓ Correct Answer: Option B

Option B correctly uses 'dog's' to show singular possession. Option A should be 'children's'. Option C implies multiple students possess multiple scores, which is plausible, but 'the dog's bone' is a clearer single possession. Option D uses 'its' as a contraction for 'it is', not a possessive.