The answer is C: Moving through the darkness.
The fact the question is asking about the adventures of a guide dog or the blind entails that it probably is a form of narrative, fiction or otherwise, which means it must be written to appeal to a reader´s fancy. So the title you should be looking for in the answer is one that is enticing or captivating at first glance, in a narrative sense. Also, semantically, and considering the reason stated previously, answer C is the only one that is interpretatively connected to a guide dog or the blind narratively.
A substance that reduces congestion. we take decongestants in order to get rid of congestion.
