【阅读选择】The ideal battery will store a lot of energy in a small package. Right now, Belcher's model battery, a metallic disk completely built by viruses, looks like a regular watch battery. But inside, its components are very small—so tiny you can only see them with a powerful microscope.
Which of the following is true of Belcher's battery mentioned in paragraph 6?
B
It is a kind of watch battery．
C
It can only be seen with a microscope．
D
It is a metallic disk with viruses inside it．
