The traffic light at three road crossings change after every 48 sec., 72 sec. and 108 sec. If they all change simultaneously at 8 : 20 : 00 hours, then at what time they will again change simultaneously?
[a] 8 : 27 : 12 hrs [b] 8 : 29 : 14 hrs [c] 8 ; 27 : 7 hrs [d] 8:29 hrs