Explain a national security challenge faced by the united states after 1990, concerning each of the following
 terrorism:
 nuclear weapons:

the answer to fill in the blank in this question would be the word resource, it is defined as the money, material or people (since human resource is a very valuable good) that a company or a person has at disposition (meaning they can use the resource as they see fit), to be able to complete a task or achieve a goal.  

what are the options so i can answer it