Given an instance of the Song class called song, what is the proper way to set the length after it has been instantiated?

public class Song
{
  private String title;
  private String artist;
  private double length;

  public double getLength()
  {
    return this.length;
  }

  public Song(String title, String artist, double length)
  {
    this.title = title;
    this.artist = artist;
    this.length = length;
  }
}

1. Correct Answer
   Incorrect Answer
   a

   song.length = 3.5;

2. Correct Answer
   Incorrect Answer
   b

   song.getLength() = 3.5;

3. Correct Answer
   Incorrect Answer
   c

   song.getLength(3.5);

4. Correct Answer
   Incorrect Answer
   d

   song.setLength(3.5);

5. Correct Answer
   Incorrect Answer
   e

   You cannot set the length, since length is private and there is no setter method.