Mastering Java: The Ultimate Quiz for 'Thinking in Java'

PrintStream is the correct answer because it is the class where the method format() is located. The other choices, System, Formatter, and String, do not contain the method format() and therefore cannot be the correct answer. System is a class that contains utility methods, Formatter is a class used for formatting data for output, and String is a class for storing and manipulating strings of characters. None of these options would contain a method specifically modeled after C's printf().