The correct options are
B Messengers to foreign countries
C Inscriptions on rocks and pillars
D Dhamma mahamattas
The devastating result of Kalinga war inclined Ashoka towards the path of Dhamma. He appointed Dhamma mahamattas, who went from place to place teaching people about Dhamma. Ashoka also used inscribed rock pillars to spread his message of Dhamma. He also sent messengers to spread the message of Dhamma to other countries like Syria, Egypt, Greece and Srilanka.