Which one of the following is the principal source of information of Ashoka's campaign against Kalinga?

Answer: Option D

The rock edict XIII gives a clue that Kalinga was a country previously unconquered, thus Ashoka's declaration of war was that of unprovoked aggression. The Kalinga war witnessed terrible manslaughter and destruction. Asoka's victory in the Kalinga war followed by remorse. Victory of morality in India and among the Greeks (Yonas), as far as where the Greek kings Antiochus, Ptolemy, Antigonus, Magas and Alexander rule.