Final answer:
To convert a StringBuilder object to a String, use the ToString() method of the StringBuilder object.
Step-by-step explanation:
To convert a StringBuilder object to a String, you can use the ToString() method of the StringBuilder object. The correct answer in this case is option a. The ToString() method returns a string representing the contents of the StringBuilder object. Here is an example:
StringBuilder stringBuilder = new StringBuilder();
stringBuilder.append("Hello");
stringBuilder.append("World");
String result = stringBuilder.toString();
In the example above, the StringBuilder object is converted to a String using the toString() method.