The correct options are
B He appointed officials, who were sent to all parts of the empire to assess and collect taxes.
C To control the officials, the emperor appointed governors and family members.
D He had spies all over his kingdom, reporting everything back to him.
According to the Arthashastra, the Mauryan empire had the most elaborate tax system of the ancient world. To collect taxes effectively, a system had been set up with officials, who were sent to all parts of the empire to assess and collect taxes. To control the officials, the emperor also appointed governors and family members. To make sure they were under control, he had spies all over his kingdom, reporting everything back to him.