The Olympic Games helped to keep peace among the pugnacious states of the Greek (world in that a sacred truce was proclaimed during the festival's month).
B) world, proclaiming a sacred truce during the festival's month D) world, for a sacred truce was proclaimed during the month of the festival
答案没问题。B确实动作发出者指代不清，可是og后面的解释带到一句“a clause is preferable to a phrase here"，为何？
