Sangitisutta 1.11.152

1.11.152

ekaṃsabyākaraṇīyo pañho, paṭipucchābyākaraṇīyo pañho, vibhajjabyākaraṇīyo pañho, ṭhapanīyo pañho.

There is a question that should be answered categorically. There is a question that should be answered analytically. There is a question that should be answered with a counter-question. There is a question that should be set aside.