Final answer:
b. Guru Arjan Dev Ji was the Sikh Guru who underwent the severe torture of being seated on a red-hot iron plate and having hot sand poured on him. This was a result of the orders of Mughal Emperor Jahangir and is a significant event in Sikh history.
Step-by-step explanation:
The guru who was subjected to the brutal torture of being seated on a red-hot iron plate and having burning hot sand poured on his body was b. Guru Arjan Dev Ji.
Guru Arjan Dev Ji was the fifth of the Sikh Gurus and he underwent this torture by the orders of Mughal Emperor Jahangir. This act of martyrdom is significant in Sikh history as it demonstrated the Guru's deep faith and commitment to non-discrimination and righteousness in the face of severe persecution.