Design a class hierarchy used to represent test papers that would be given in school. It should include at least the following:

FillInTheBlankQuestion

A fill in the blank question is a kind of question where the correct answer fills in a missing word in the provided text. For example. " _____ was the 16th US President."

Each FillInTheBlankQuestion has:

points

Number of points earned for answering the question correctly.

difficulty

Range of difficulty ranging from the constants MIN_DIFFICULTY to MAX_DIFFICULTY.

answerSpace

Amount of space that should be left on the paper so that the test taker can fill in the answer. This can be represented as the number of lines on the page.

questionText

The text of the question, e.g., "How much wood would a woodchuck chuck if a woodchuck could chuck wood?"

correctAnswer

The correct answer to the question.

For each FillInTheBlankQuestion, we should be able to create a String representation of the question as it should be presented to the student during a Test. This should include the blank space. We should also be able to create a String representation of the question which includes the correct answer, such as one that a grader might use when grading a paper.

In a test representation, this might look something like:

______ was the 16th US President.

and in an answer key representation, it might look something like:

___Abraham Lincoln___ was the 16th US President.