The Zip Code, the numerical system, was publicized in ______.

A．read addresses quickly.
B．handle mail by machines.
C．sort out mail very fast.
D．do all of the above.

A．surface constructions then can be more aesthetically planned
B．historic landmarks then can be better preserved.
C．there won't be skyscrapers blocking our view.
D．there will be more green land left untouched.