There ___________ a ruler, a pen and some pencils in the pencil-box. They're ___________.[ ]

A. are, her

B. are, she

C. is, hers

D. are, hers

某些食品包装袋内有一小包物质，用来吸收氧气和水分，以防止食品腐败，常称“双吸剂”，下列物质属 于“双吸剂”的是[ ]

A．铁粉

B．炭粉

C．氯化钙

D．生石灰