Correct answer: C. They may exaggerate the ruler's achievements
Explanation: A Prashasti is a formal eulogy or praise inscription composed to celebrate a ruler, dynasty, or patron. Its main limitation as historical evidence is that the author usually intended to glorify the ruler rather than provide a neutral account. Victories may be magnified, failures omitted, and enemies described negatively. Consequently, option C is correct: a Prashasti may exaggerate the ruler's achievements. This does not make it useless; historians can still use it for information about political claims, titles, ideals, and the language of royal power, while comparing it with other evidence. Option A is unrelated, option B is false because many Prashastis are inscriptions, and option D wrongly places them in the modern news category.