What is the converse of the following conditional statement? "If this month is September, then next month ends in the letter r." Determine the validity of the converse and give a counterexample if the converse is not valid. If next month ends in the letter r, then this month is September. The converse is valid. If this month is not September, then next month does not end in the letter r. The converse is valid. If next month ends in the letter r, then this month is September. The converse is invalid; a counterexample is December. If this month is not September, then next month does not end in the letter r. The converse is invalid; a counterexample is December.