D. Opportunity cost
Because in the end if you want something you have to work for it, no matter what. Everything generally costs money in this world
<span>the privilege, claimed by the president for the executive branch of the US government, of withholding information in the public interest.</span>
The answer is: <span>the directionality problem
</span><span>the directionality problem refers to a type of problem in which the cause and effect relationship is not known.But even though the relationship is not known, we can now for sure that the problem is exist because it shows obvious effect/symtomps.</span>
