单选题 Partha has withdrawn its troops from Baltia after five years of occupation. Earlier this year the country of Cardena began shipping mules to Baltia's resistance fighters to facilitate transport of weapons across Baltia's mountains to the battle areas. Cardena's diplomats now claim that without Cardena's aid to Baltia's resistance fighters, Partha would not have withdrawn.
Which of the following, if true, casts the most serious doubt on the accuracy of the assertion of Cardena's diplomats?

【正确答案】 C
【答案解析】