What was a serious risk commonly faced by traders on the Silk Road?
(A) attacks by wild dogs
(B) swarms of mosquitoes
(C) extreme temperatures
(D) flooded river crossings
From Internet:
Like other deserts, the Gobi Desert is arid, and therefore the biggest challenge facing those who choose to traverse it is to obtain enough water for themselves as well as for their camels.
This would lead me to C.