Madhvaon Brahma Sūtra 1.4.6
Dvaita Vedānta
Numbered 1.4.7 in this text
Sūtra
त्रयाणामेवचैवमुपन्यासः प्रश्नश्च
trayāṇāmevacaivamupanyāsaḥ praśnaśca
Sūtra translation
And (because of the whole Upanishad dealing) with the explanation of, as well as the question on, the same three topics.
For the Kâthaka Upanishad treats only of the three boons prayed for by Nachiketas, viz., reconciliation to his father, the sacred fire leading to svarga, and the nature of the Supreme Lord (to be reached when released from the body), and(Yama’s) answers regarding the same three points of enquiry. A request * to know what is not (already) known is also called a question. From this explanation given in Smriti, there is no difficulty caused by the use (in this aphorism) of the word * question.’