Final answer:
John Rawls is the thinker who advocated for welfare rights, proposing a theory of justice that includes fair treatment and support for the least advantaged in society.
Step-by-step explanation:
The advocate of welfare rights among the thinkers listed is John Rawls. Rawls's ideas, as articulated in his seminal work A Theory of Justice, are supportive of the notion of a welfare state, in which the well-being of citizens must be a vital component of our agreement to obey a government. Among the given options, Nel Noddings is the advocate of welfare rights. Nel Noddings is an American philosopher who has written extensively on the topics of caring in education and ethics of care. This theory is based on the idea of the veil of ignorance, where one designs a society without knowing their position within it, ensuring that the individual's decisions are fair and just for all members of society, including support for the least advantaged.