The dialogue between the young boy Nachiketa and Yama, the god of death, is found in the:

The famous dialogue between the boy Nachiketa and Yama, the god of death, is found in the Katha (Kathopanishad) Upanishad.

The story of Nachiketa:

• Nachiketa's father, Vajashravas, performed a sacrifice in which he was supposed to give away all his possessions, but he gave away only old and useless cows.
• Nachiketa repeatedly asked his father, "To whom will you give me?"
• In anger, his father said, "I give you to Death (Yama)."
• Nachiketa went to the house of Yama, who was away, and waited there for three days without food.
• On his return, Yama was sorry for making a guest wait, and granted him three boons (wishes).

The three boons:

• First: that his father should be calm and welcome him back.
• Second: knowledge of the fire sacrifice that leads to heaven; Yama taught him this, and it came to be called the "Nachiketa fire".
• Third: knowledge of what happens to a person after death, whether the self continues to exist.
• Yama tried to tempt him with wealth, long life and pleasures instead, but Nachiketa refused, saying that all these things are temporary.
• Finally, Yama taught him about the eternal self (atman), which is not born and does not die.

Teachings of the Katha Upanishad:

• The difference between "shreyas" (the good) and "preyas" (the pleasant).
• The image of the chariot: the body is the chariot, the self is its owner, the intellect is the charioteer, the mind is the reins, and the senses are the horses.
• The famous line "Uttishthata jagrata prapya varan nibodhata" ("Arise, awake, and stop not till the goal is reached"), which Swami Vivekananda popularised.

About the Katha Upanishad:

• It belongs to the Krishna Yajurveda.
• It is one of the principal Upanishads, in verse form.

Why not the other options?

• ✗The Kena Upanishad asks "by whom" the mind and senses are directed.
• ✗The Prashna Upanishad is in the form of six questions.
• ✗The Aitareya Upanishad belongs to the Rigveda.