The correct answer is A) high unemployment.
The Roman Empire faced all of the following economic problems during its decline except high unemployment.
The Roman Empire decline was due to many reasons. Barbarian tribes invaded Roman territories. The last one was the invasion led by barbaric leader Odoacer, that deposed Emperor Romulus Augustus in 476. Another reason was the overspending in so many wars and trying to defend territories that were so far away from Rome. This caused a financial crisis in the Empire. One more factor was the government corruption that provoked political instability in the Empire.