Explicit knowledge is
Knowledge that is codifiable. (that is, it can be written down and transferred without losing much of its richness)
The Peloponnesian War weakened the Greek city-states and it divided them. This gave Phillip 11 of Macedon the opportunity to move in and conquer them in their weakened, non-united condition and they were never to get their original strength back again. The Peloponnesian war was very debilitating to the Greek city-states.
Tariff makes the most sense. Embargo is a ban on goods or a country, subsidy is money granted from the government to a business and has nothing to do with trade, quota is a limited amount of a product and again doesn't really have anything to do with trade.