In Addition to the Mamluk Power in Egypt, Why Did

In addition to the Mamluk power in Egypt, why did the khan of the Ilkhan horde not follow up on the conquest of the Islamic heartland?

A) The forces of the Christian crusader states were likely to bring the powerful armies of western Europe into the struggle against the Mongols.
B) The khan died, leaving a minor as the ruler of the Ilkhan horde.
C) The successor of Batu as ruler of the Golden Horde, Berke, had converted to Islam and was a potential ally of the Mameluks.
D) The Ilkhan horde dissipated into rival clan groups following their defeat at the hands of the Mameluks.