Whom did Asoka appoint to spread the message of 'Dhamma'?

Dhamma Mahamatya

The correct answer is Option 2 - Dhamma Mahamatya

 Asoka appointed Dhamma Mahamatyas to spread the message of 'Dhamma'.

Asoka also tried to hold his empire together by propagating dhamma, the principles of which, as we have seen, were simple and virtually universally applicable. This, according to him, would ensure the well-being of people in this world and the next. Special officers, known as the dhamma mahamatta, were appointed to spread the message of dhamma.