If the united states threatens to use military force to keep shipping lanes open near the spratly islands in the south china sea despite chinese claims that the islands are part of their territory, which strategy is the united states using?

Deterrence is the correct answer.

In a broader term, deterrence is the art of convincing someone not to do something. In International Relations, deterrence is a military strategy used by leaders of one country to leaders of the other country. It prevents military attacks from taking place by using the threat of reprisal in an effective manner.  

can you tell me where are the ansawer choices

for many centuries there were important factors which the economies of the muslim empires developed increasingly. they applied economic procedures in production, investment, finance, taxation and property. they used to tax certain goods (for example: harvest), they charged interest on money lent, they signed contracts with merchants; they relied on a common currency, and they used checks as well as promissory notes. with the money collected by means of taxation, the government provided the needy with an income. in addition, trading networks covered huge distances, so far regions started to have contact and exchange goods. this trade network covered areas of asia, africa and europe.