GWD 21-27

Q27:

The electronics company has unveiled what it claims to be the world’s smallest network digital camcorder, the length of which is that of a handheld computer, and it weighs less than 11 ounces.

1. to be the world’s smallest network digital camcorder, the length of which is that of a handheld computer, and it weighs
2. to be the smallest network digital camcorder in the world, which is as long as a handheld computer, weighing
3. is the smallest network digital camcorder in the world, which is as long as a handheld computer, and it weighs
4. is the world’s smallest network digital camcorder, which is as long as a handheld computer and weighs
5. is the world’s smallest network digital camcorder, the length of which is that of a handheld computer, weighing

答案B，但那个weighing 是做什么成份啊？ 我怎么就认为应该是 "and weighs"更好呢？请指教