ii. character mode:

"In character-at-a-time mode, most text typed is immediately sent to the remote host for processing." This means the number of TCP segments is equal to the number of characters in the command. The command "cp file1 file2" has 15 characters (including white space and carriage return). So the number of TCP segments for character mode is 15.

iii. line mode

" In old line-by-line mode, all text is echoed locally, and (in most cases) only completed lines are sent to the remote host." This means the number of TCP segments is equal to the number of lines of commands. In our case, we just issued one command, so the number of TCP segments is 1.

i. default mode

" If telnet is issued with arguments, it performs an open subcommand with
those arguments, then enters input mode. Once a connection is opened, tel-
net attempts to enable the TELNET LINEMODE option. If this fails, telnet
reverts to one of two input modes: either character-at-a-time or old line-
by-line mode, depending on what the remote system supports."

This means the default mode is LINEMODE. So the number of TCP segments is 1 in default mode.