Hi,<br/><br/>1. D-Day commenced on one morning in June 1944.<br/><br/>2. D-Day commenced on 6 June 1944.<br/><br/>3. D-Day commenced on one morning on June 1944.<br/><br/>4. D-Day commenced in 6 June 1944.<br/><br/>5. D-Day commenced at 6:30 am on 6 June 1944.<br/><br/>Which of these sentences are the grammatically correct?<br/><br/>Thank for your attention.