Anguttara nikaya (bhikkhu bodhi translation)
4.42 (2) Questions
“Bhikkhus, there are these four ways of answering questions. What four?
(1) There is a question to be answered categorically;
(2) there is a question to be answered after making a distinction;
(3) there is a question to be answered with a counter-question; and
(4) there is a question to be set aside. These are the four ways of answering questions.
” One kind is given a categorical answer, another is answered after making a distinction; to the third, one should raise a counter-question, but the fourth should be set aside. When a bhikkhu knows how to answer each type in the appropriate way, they say that he is skilled in the four kinds of questions.