Final answer:
Minor parties typically impact a two-party system by shaping political agendas and discourse, influencing major parties to adopt new issues, despite rarely winning major elections due to the winner-take-all system.
Step-by-step explanation:
The potential impact of minor parties in a two-party system such as the United States is not typically to dominate in national elections nor to foster strong bipartisan cooperation. Instead, minor parties often play a more nuanced role. Based on the various references provided, the correct answer to the student's question would be B) Shaping the political agenda and discourse. Minor or third parties often highlight specific issues that major parties might overlook or consider too risky to address. Over time, the two major parties may absorb these issues into their platforms to appeal to a broader electorate. While third parties rarely win major elections due to the winner-take-all system, they can influence policy debates and voter perspectives, contributing to a dynamic political environment where major parties may shift their stances based on the concerns raised by third parties.