"He likes to cook with an aunt."
Translation:Він любить готувати з тіткою.
"Він любить варити з тіткою/цьоцею." is more accurate. And should be marked correct.
This is s very unlikely English sentence. He liked to cook with aunt/aunty/his aunt are all much more likely than 'an aunt'. The latter vaguely implies he has hundreds of aunts or works for an 'aunt convention', or something. Better to use a 'realisitic' sentence for teaching purposes.