The World Health Organization (WHO) was founded on April 7, 1948. The WHO's constitution was adopted by the International Health Conference in New York in 1946. The WHO is a United Nations specialized agency. 

The famous treaty between Russia and Napoleon in 1807, which contributed to Napoleon reaching the peak of his height, was the "Treaty of Tilsit." Therefore, the correct answer is:

(C) Treaty of Tilsit

The Peninsular War took place from 1808 to 1814 on the Iberian Peninsula. It began when Napoleon invaded Spain and Portugal. Widespread resistance from Spanish and Portuguese forces, along with guerrilla warfare, led to a protracted conflict. The war significantly weakened Napoleon's forces and contributed to his strategic challenges. The conflict ended with the defeat of French forces in the region by the Sixth Coalition, consisting of British, Spanish, and Portuguese allies.