ANSWER PL FAST Refer to the passage.
Which of the following best explains the Mongolian
khans' difficulty with bringing Vietnam under the Pax
Mongolica?
"The Chams from the time of King Wen knew the art of
fortification. They protected their cities with walls in
brick. The citadels and strong places served as depots
for materials of war.
The Cham subjects helped the officials by giving
forced labour and service to the king. The landlords
gave a tax in kind which was measured by jak, a
measure of whose value we are quite ignorant. Half of
this tax went to the landlord and the other half to the
king, except in the case where the latter had made a
gift of it to the temples or monasteries. We find the
kings always busy making grants to temples or
monasteries."

A)The policy of defense and fortification to prepare
villages and cities for times of war
B) The policy of nonviolent resistance and diplomatic
negotiation, supported by Hindu religious leaders
C) The policy of establishing strong trade ties with the
Yuan dynasty to deter a conquering force
D) The policy of forced labor to quickly establish a
conscripted army when facing attack