The elastic clause allows Congress to: A: make temporary treaties with foreign countries.
B: regulate trade between states.
C: stretch its powers to meet new needs.
D: tax U.S. citizens in times of economic crisis

The correct answer is:  

        the "Appalachian Mountains " .

                           or ;  write as:   "Appalachian Mtns. "

                           or ;  write as:   "Appalachian Mountain Range" .

                           or ;  write as:   "Appalachian Mtn. Range " .

Note:   The actual "question, itself" ;  should be written as:  

                {something to the effect of} :

      " To what mountain range does the following description refer?

            "This is the eastern North American range that reaches from Alabama in the South to Canada in the North.                                                  

             Mt. Mitchell is the highest point in this range. "

Hope this answer is helpful to you!

     Best wishes to you in your academic pursuits

              — and within the community!