疾病监测采用的方法属于（）

A.描述性研究

B.分析性研究

C.实验性研究

D.理论性研究

E.包括以上四种

Partha has withdrawn its troops from Baltia after five years of occupation.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 Cardena’s diplomats now claim that without Cardena’s aid to Baltia’s resistance fighters, Partha would not have withdrawn.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

A．No precise figures are available concerning the number of mules shipped to Baltia.

B．During the past year, Cardena shipped weapons and food, as well as mules, to resistance fighters in Baltia.

C．Last year a new government took power in Partha and decided that national interests were not served by the occupation of Baltia.

D．Two years ago Partha had no plans to reduce its forces in Baltia.

E．(E) Resistance fighters in Baltia fought for five years against Partha’s occupying troops.