Final answer:
The national interest argument for protectionism is to prioritize domestic industries and workers to avoid dependence on imported supplies that could lead to vulnerabilities. So, the correct answer is option b.
Step-by-step explanation:
The national interest argument for protectionism is that a nation should prioritize its domestic industries and workers. Option (b) 'To prioritize domestic industries and workers' is the correct answer to the question of what the national interest argument for protectionism with regard to certain products is.
This argument states that importing key products can make a country vulnerable if it becomes too dependent on these imported supplies, risking a cutoff. Instead, it might be wise to stockpile resources or use foreign supplies strategically rather than impose restrictions that could prevent dependency on them.
So, the correct answer is option b.