Step 1: Recall the adoption of the UDHR.
The United Nations General Assembly adopted the Universal Declaration of Human Rights (UDHR) on December 10, 1948. This landmark document established fundamental rights and freedoms for all people regardless of nationality, race, or status.
Step 2: Identify the observance date.
Since 1950, December 10 has been observed as International Human Rights Day every year to commemorate the date of the UDHR's adoption. It is one of the most widely recognized UN observance days globally.
Step 3: Eliminate the distractors.
October 24 is UN Day. November 10 is World Science Day. December 11 has no major human rights association. The answer is firmly and memorably December 10 - the UDHR adoption date.
\[ \boxed{\text{10th December}} \]