In the diagram, which must be true for point D to be an orthocenter?
O BE, CF and AG are angle bisectors.
O BE L AC, AG L BC, and CF L AB.
O BE bisects AC, CF bisects AB, and AG bisects BC.
O BE is a perpendicular bisector of AC, CF is a
perpendicular bisector of AB, and AG is a
perpendicular bisector of BC.