Entire year is your answer.
When
you have a child born during the tax year, you need to say the child lived
with you all year, which is the correct
tax response for a child who was born or died during the
year.
From
<https://ttlc.intuit.com/questions/4170282-i-tried-to-claim-my-son-but-the-money-that-they-re-giving-...>
