Answer:
Step-by-step explanation:
Since there are 4 cities, there are (4-1)! = 6 possible routes. Half of those are the reverse of the other half, so there are 6/2 = 3 different possible routes. All of those are listed among the answer choices, along with their cost. All you need to do is choose the answer with the lowest cost:
ACDBA, $900
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At $960, the other two routes are higher cost.
