The local host on a small network is named Earth. There is also a remote host on the network named Saturn. The system administrator of the network is in the /u/tmp directory of Earth, and starts an ftp to Saturn as root. Which of the following sequence of commands issued from the local host, Earth, will:()。
1.Check to see if there is an a.out file on remote host Saturn.
2.Change to the /u/new directory on Earth.
3.Transfer a.out from Earth to Saturn.