Final Answer:
The 40th parallel north sets the border between Nebraska and Kansas. This geographical line plays a crucial role in defining the territorial boundaries between the two states, with the parallel serving as a clear demarcation point for their separation. so, the correct answer is a) Kansas.
Step-by-step explanation:
The 40th parallel north is a line of latitude that runs east-west across the United States. In the case of Nebraska, it serves as the southern border with Kansas. This geographic marker is vital for establishing boundaries and has practical implications for governance, jurisdiction, and land use in the region.
While neighboring states like Colorado, Wyoming, and Oklahoma are in close proximity, it is the 40th parallel north that specifically designates the border between Nebraska and Kansas.
Therefore, the correct answer is a) Kansas.