UPSC CSE Prelims 2011
The problem involves determining the total number of possible routes for a journey comprising sequential stages. The fundamental principle applicable here is the multiplication principle of counting. This principle states that if an event can occur in 'm' distinct ways, and following this, another independent event can occur in 'n' distinct ways, then the total number of ways both events can occur in sequence is m × n.
Applying the multiplication principle, the total number of possible routes from city A to city C is 4 × 6 = 24.
Options 2, 3, and 4 are incorrect as they do not apply the appropriate combinatorial principle for sequential events.