Why do many scholars believe that Rogier van der Weyden's portrayal of St. Luke might be a self-portrait of the artist?
1) Because the facial features of St. Luke resemble those of Rogier van der Weyden
2) Because Rogier van der Weyden often included self-portraits in his paintings
3) Because there is evidence that Rogier van der Weyden used himself as a model for St. Luke
4) Because other artists of the time also portrayed themselves as St. Luke in their paintings