Answer:
The attacks reduced public support for open immigration laws.
Step-by-step explanation:
Following the terrorist attack of September 11, 2001, how the immigration debate in the united states was shaped by the terrorist attacks was that from the government, there is more increase in the level of security or process of obtaining visas, especially to the developing nations.
Hence, the process of getting asylum, refugee requests, etc became more strict.
Similarly, the general perception of Americans changed in terms of supporting the easy means of immigration into the United States.
Hence, the right answer to the question is that "The attacks reduced public support for open immigration laws."