The Pax Mongolica Refers to Which of the Following

The Pax Mongolica refers to which of the following?

A) a period in which the balance of power between the Mongol khanates permitted greater trade and travel throughout Afroeurasia
B) a peace treaty signed between the pope in Rome and the leaders of the four great Mongol khanates
C) an alliance between the Mamluk state centered in Cairo and the khanate of Iran and Iraq
D) a treaty signed among the four great khanates stating that they would not attack one another