Answer should be "E" - solution goes like this:
Bus - A has start time of an hr so completes after 9 HRs of bus B's starting.
A has following pattern in term of B's timing - 9,19,29,39... Hrs.
whereas Bus B has following pattern: 15,30,45,60...Hrs
Bus B has all hrs as multiple of 15 that is equal to 3*5, which can never have multiple/LCm in terms of figure ending at 9 (viz. 9,19,29 and so on..)
Whats the OA ?
Perseverance, Hard Work and self confidence