Explanation: While all these answer choices might be reasons for the Tang collapse, the correct answer must be substantiated by the passage. Eliminate (B) because the passage specifies that the Tang armies are heading to the frontiers. Eliminate (C) because the passage makes no mention of religion, let alone religious changes. Eliminate (D) because it is too extreme—the bureaucracy is competent enough to function, even in times of great duress as the poem suggests. The passage also doesn’t specify that the emperor is a bad leader, just a harsh one.