The correct answer is C) washing their clothes.
What the Mongols avoided doing because they claimed it would anger the gods was washing their clothes.
The Mongols did not bathe because they had the belief that dragons controlled the water cycle. If they bathe, they would contaminate the water, affecting the dragons, and Mongols did not want to anger the dragons. So Mongols, never bathe and never washed their clothes. The smell also represented a weapon that affected their enemies.