Due to so many unexplained difficulties and bad omens, the Majesty is humbled and concerned. . . . To alleviate the situation, all policies that cause the public inconvenience, if not urgent, should be stopped. . . . Policies temporarily stopped include the voyages to foreign countries, horse-trading with the remote western and northern areas.

What Ming political and economic policy does this excerpt provide an example of?

commercialism
Confucianism
kowtowing
isolationism