Suppose That Sock Refers to a TCP Socket Connected to Another

Multiple Choice

Suppose that sock refers to a TCP socket connected to another machine, and in is aScanner. Which code sends the string "Who is there?" to the other machine, receives the return answer, and then prints it?

A) PrintWriter pw = new PrintWriter(sock.getOutputStream() .println("Who is there?") ) ;
InputStream instream = sock.getInputStream() ;
Scanner in = new Scanner(instream) ;
System.out.println(in.nextLine() ) ;
B) PrintWriter pw = new PrintWriter(sock.getInputStream() ) ;
pw.println("Who is there?") ;
pw.flush() ;
InputStream instream = sock.getInputStream() ;
Scanner in = new Scanner(instream) ;
System.out.println(in.nextLine() ) ;
C) PrintWriter pw = new PrintWriter(sock.getOutputStream() ) ;
pw.flush("Who is there") ;
InputStream instream = sock.getInputStream() ;
Scanner in = new Scanner(instream) ;
System.out.println(in.nextLine() ) ;
D) PrintWriter pw = new PrintWriter(sock.getOutputStream() ) ;
pw.println("Who is there?") ;
pw.flush() ;
InputStream instream = sock.getInputStream() ;
Scanner in = new Scanner(instream) ;
System.out.println(in.nextLine() ) ;