Which sentence uses 'its' correctly?

• A. The dog wagged its tail.
• B. The dog wagged its tails.
• C. Its tail wagged the dog.
• D. It’s tail wagged the dog.

Answer: (A)

Using its correctly marks ownership. Its is a possessive determiner, showing that something belongs to the subject. Here, the tail belongs to the dog, so the natural, correct phrasing is The dog wagged its tail.

The other forms don’t fit as well: using tails would imply the dog has more than one tail, which is unusual; starting with Its tail wagged the dog can be confusing because the antecedent isn’t clear in isolation; and It’s would be a contraction of it is, which doesn’t work for showing possession here.