Answer : 4. "नवंबर के तीसरे गुरुवार "
Explanation :

From the year 2002, UNESCO started the tradition of celebrating World Philosophy Day. In the year 2005, it was decided in the UNESCO conference that World Philosophy Day will be celebrated every year on the third Thursday of November. World Philosophy Day is celebrated in honor of those philosophers who provided space for free thoughts to the entire world. The purpose of this day is to encourage all the people of the world to share the philosophical heritage and to bring openness to new ideas as well as to inspire discussion among intellectuals and civil society to fight social challenges.