Back then senators weren't elected through popular vote. Abraham had to be appointed by state legislatures
There should really be an option D: Nonexistent.
But, if I HAD to choose, I suppose...C.
Answer:
A. A region can be studied over long spans of time, but a period applies to a specific time span.
Explanation:
<em>Regions</em><em> </em>are areas/locations. Ex. "The Midwestern Region." So, regions can be studied for as long as that place exists.
<em>Periods</em><em> </em>are set amounts of time. Ex. "A period of 100 years." So, periods are studied within that specific time span.