题目
--Have you heard about the news that several Chinese drones（无人机）gave a wonderful performance in Saudi Arabia（沙特）?
--Of course. of drones is up to 6000.（ ）
--Of course. of drones is up to 6000.（ ）
A.
thousands，A number
B.
thousands.The number
C.
thousand，A number
D.
thousand，The number
知识点：说明文;判断推理;文中细节章节：未标注