On ________ Friday when Tom was having an art lesson，as he had no color pencils with him，he drew ________ blue sun with his pen.

A．/；the

B．/；a

C．the；the

D．a；a

按照参与交易的对象分类，网上商店最适合属于哪一类（）

A.B2B

B.B2C

C.B2G

D.C2C