The correct answer is A, as the Balfour Declaration declared Britain would support a Jewish state in Palestine.
The Balfour Declaration (dated November 2, 1917) was a formal public manifestation of the British government during the First World War, to announce its support for the establishment of a "national home" for the Jewish people in the Palestine region, which then was part of the Ottoman Empire. The Declaration was included in a letter signed by British Foreign Office Minister Arthur James Balfour and addressed to Baron Lionel Walter Rothschild, a leader of the Jewish community in Britain, for transmission to the Zionist Federation of Great Britain and Ireland. The text was published in the press on November 9, 1917.