Final answer:
The Borgen Project argues that poverty-reducing legislation should address the root causes of poverty and inequality.
Step-by-step explanation:
The Borgen Project's main argument for supporting poverty-reducing legislation is B) to address the root causes of poverty and inequality. The organization believes that by focusing on the underlying factors that contribute to poverty, such as lack of access to education, healthcare, and job opportunities, lasting change can be achieved. They advocate for policies that aim to create systemic change and provide equal opportunities for all.