What is the most advantageous filing status allowable for Aurora?

Aurora and Oscar separated in 2017 and divorced in October 2019. She earned $40,000 in wages and paid more than half the cost of keeping up her home in 2019.
Aurora and Oscar have a son, Milo, who is 17 years old and unmarried.
Aurora signed Form 8332 (Release/Revocation of Release of Claim to Exemption for Child by Custodial Parent) allowing Oscar to claim Milo in 2019.
Milo is a full-time student working towards a degree in computer information systems. Milo lived on campus during the school year and spent the summer at home with his mother.
Milo does not a have a felony drug conviction and is not a qualifying child for anyone except Aurora.
Aurora paid $5,000 of Milo's tuition that was not covered by his scholarship.
Aurora provided more than half of her son's support and all the cost of his room and board on campus.
Milo's only income was $3,800 in wages and $400 of dividend income. He had no federal or state tax withholding.
Aurora and Milo are U. S. citizens and have valid Social Security numbers.

I was thinking single since she gave up her right to claim Milo, but I'm not sure. Would she be able to file as head of household?