There are trains travelling on 4 parallel tracks. The frequencies of trains traveling on these tracks at equal interval of time are 4, 6, 8, 12 per hour respectively. If all trains start at 7 AM, after how much time will all the trains start together from the same place?
A. 1 Hour
B. 12 Hours
C. 24 Hours
D. 1/2 hours
E. 1/4 Hours
A. 1 Hour
B. 12 Hours
C. 24 Hours
D. 1/2 hours
E. 1/4 Hours