Which is the earliest&

Which is the earliest line in the following code after which the object created on the line marked （0） will be a candidate for being garbage collected， assuming no compiler optimizations are done？ （）  public class Q76a9 {   static String f（） {   String a = "hello"；   String b = "bye"； // （0）   String c = b + "!"； // （1）   String d = b；  b = a； // （2）   d = a； // （3）   return c； // （4）  }   public static void main（String args[]） {   String msg = f（）；   System.out.println（msg）； // （5）   }   }  

• AThe line marked （1）.
• BThe line marked （2）.
• CThe line marked （3）.
• DThe line marked （4）.
• EThe line marked （5）.