Explanation:

- The Universal Declaration of Human Rights is a milestone document.

- Option 1: December 1, 1948 – This date is incorrect. There's no significant historical event related to the UDHR on this day.

- Option 2: December 10, 1948 – This is the correct date. On this day, the United Nations General Assembly adopted the UDHR. It outlines fundamental human rights that are universally protected.

- Option 3: December 11, 1948 – This date is incorrect. No notable event related to the UDHR happened on this day.

- Option 4: December 31, 1948 – By this date, the UDHR had already been adopted earlier in the month.