According to the passage, the first full-scale giant recycling plants will ______.

A．There will be no rubbish after the plants have been built.
B．Recycling plants will be in great need in some big cities.
C．The plants can only process paper and rubber but not steel or copper.
D．We don' t have a very good way of sorting and separating the rubbish.

A．they can be of great help to the protection of environment
B．it is more expensive to process wastes in a farther dump
C．they can make the wastes into something that is useful
D．they can produce a lot of energy for the local residents