What are the coordinates of this polygon's vertices?
(1, 1), (3, 1) and (1, 4)
(1, 1), (5, 1) and (1, 4)
(1, 1), (1, 5) and (4, 1)
(1, 1), (5, 1) and (4, 1)
(1, 1), (1, 5) and (1, 4)
