Structural defense policy has to do with A. plan for deployment of troops in times of war B. the development of a collective security arrangement...

The best way to answer this question is to say that structural defense policy has to do with budgeting for the military.  This means that Option C is the best answer.

Structural defense policy can be defined as policy that has to do with what the military spends its money on.  Structural defense policy has to do with things like deciding which weapons systems or platforms to keep spending money on.  It has to do with deciding what bases to keep open and what bases to close.  In other words, it has to do with the structure of the military.  It has to do with deciding what the “bones” of the military will look like.  With this in mind, Option C is really the only possibility.