Confederate soldiers during the civil war enjoyed a geographic advantage over union soldiers because a) southern troops disrupted union trade routes. b) the union could not break the southern coastal blockade. c) the railroad lines could not penetrate confederate lands. eliminate d) most of the battlefields were located in confederate states

Okay, so D is an accurate answer, but I'm not sure if it would be correct in this context because although most of the battles did take place in the Confederate states, that really wouldn't be a reason why Confederate soldiers had a geographic advantage.

The best answer would be C- the railroad lines could not penetrate Confederate lands. The South was mainly rural and so their were not a lot of rail lines down there at that time, meaning the Union couldn't quickly get their troops down to fight and instead had to trek many miles to confront the Confederate soldiers. 

The dethroned emperor!