The correct answer is D) railroad tracks and total population.
<em>During the Civil War, the resource areas where the Union held 71% of total resources were railroad tracks and total population.</em>
As we can see in the graphic attached, the Union considerably had more resources than the Confederacy. For instance, regarding horses and food crops, the Union had 72% for each one. The Confederacy lied way behind with just 28%. Regarding soldiers, the Union had 67% and the Confederacy 33%. In railroad tracks, the Union had 71% and the Confederacy 29%. In factories, the Union had 86% and the Confederacy just 14%. Regarding bank deposits, the Union had 81% and the Confederacy 19%. Finally, regarding population: the Union 71%, the Confederacy, 19%.