With the successful launch of Tiangong-I, which was ______ breakthrough in space field, China's space dream took a step closer to ______ reality.

A．a; /

B．the; a

C．a; the

D．the; /

如图A所示为某种免疫过程示意图，图B表示参与该过程的b细胞局部放大示意图。据图K29­3回答下列问题：

b细胞为（），溶酶体分解抗原的过程在免疫学上属于（）