Final answer:
The appropriate test for the city planner's hypothesis is the matched pairs t-test (c). This test is used when comparing the means of two related groups.
Step-by-step explanation:
The appropriate test for the city planner's hypothesis is the matched pairs t-test (c). This test is used when comparing the means of two related groups, which is the case here where the city planner is comparing traffic patterns at two different intersections over time. The null hypothesis would state that there is no mean difference in the number of cars passing through the two intersections during each of the 12 time intervals.