Following Chinggis Khan?s Death, What Was the Provision for the Administration

Following Chinggis Khan?s death, what was the provision for the administration of the empire?

A) It was divided into four regional kingdoms, or khanates, ruled by his sons and grandsons.
B) It was centralized with a Mongol bureaucracy located at the Chinese capital of Tatu.
C) The empire immediately fragmented into its constituent tribes and clans.
D) It passed as a single government with its capital at Karakorum to Chinggis Khan?s oldest son.