challenge: What is the origin of the Irish surnames Ó hÉideáin and Ó hÉidín?
  
  A. Originating from the Irish word for 'warrior' or 'brave'
  B. Derived from the Irish word for 'stronghold' or 'fortress'
  C. Meaning 'descendant of Éideán' and 'descendant of Éidín', derived from the Irish word for 'clothes' or 'armour'
  D. Associated with the Irish word for 'king' or 'ruler'
  Answer: 