You didn't supply us with choices, but these are three prominent documents I would name:
The Magna Carta (1215), which asserted noblemen's rights in relationship to the king. It set the principle of rights which would later be expanded.
The Bill of Rights (1689), which was an agreement made with King William III and Queen Mary II as they came over from the Netherlands to take up the royal throne of England after the so-called "Glorious Revolution" of 1688.
The Reform Act (1832) which began a significant expansion of who had voting rights within the British nation. In those days, voting rights were tied to property ownership and property values. The Reform Act allowed those who rented properties above a certain value to vote also, thus increasing the number of men who had voting rights. Further expansions of voting and parliamentary rights would follow until all men--and women ages 30 and older--were granted voting rights in 1918.
