Amnesty International is

Amnesty International is a global human rights movement, so B is correct. It was founded in London in 1961 by the lawyer Peter Benenson after he appealed for two Portuguese students jailed for toasting freedom. Its work is campaigning and research: documenting abuses, adopting prisoners of conscience, and pressing governments on torture, the death penalty and unlawful killings. It won the Nobel Peace Prize in 1977.

Why the others fail:

• A is wrong because the UN's refugee agency is UNHCR. Amnesty is independent of governments and is not a UN body.
• C is wrong because Amnesty is non-governmental, but its mandate is human rights, not poverty relief. Relief for the poor is the field of organisations like Oxfam or CARE.
• D is wrong because Amnesty is not intergovernmental; its membership is individuals and national sections. Medical relief in war zones is done by groups such as Médecins Sans Frontières.

Core concept: the difference between NGOs, intergovernmental bodies and UN agencies. For Mains (GS-II), it links to the role of civil society in rights advocacy and to how India's NHRC relates to international human rights mechanisms.

Trap: the word "non-governmental" in option C pulls many aspirants away. Every NGO has a specific mandate, and the question asks what Amnesty does, not just its legal form.