If the Organizers wants to ensure that the number of participants at S gets evenly distributed along streets from S to A, from S to B, and from S to D, then a feasible set of task time(in hours) at junctions A, B, C, and D respectively to achieve this goal is:
0,5,4,1
From the given options
It is very likely that option (d) is selected. But if all the five routes has the same time taken, then there will be an equal number of participant in all the five routes i.e. 20% in each route.
But then the percentage of participant in
S-A = 20%
S-B = 40% (As there are two routes involving S-B)
S-D = 40% (For the same reason as above)
But here the given condition that number of participant in S-A is equal to that in S-B, which in turn is equal to S-D is not satisfied.
As S-A = S-B = S-D.
Of the routes, that can be used the number of routes involving S-A must be the same as S-B, which in turn is same as that as S-D. It happened in only option (a).