Duke and his wife were legally divorced in 2021. After the divorce, Duke retained physical custody of their son. Duke received the following amounts from his ex-wife, on behalf of their son or as ordered by the court through a divorce decree:

• Court-ordered child support of $2,000 per month.
• Court-ordered alimony of $1,000 per month.

How much of this income should be reported on Duke's federal return?

$0

$12,000

$24,000

$36,000