Task: Question Answering
Input (English): Background Paragraph: The refraction of waves across boundaries operates similarly to the method by which tanks are steered. Tanks do not have a steering wheel. Instead, they have an accelerator to produce forward motion and separate brakes on each tread. The operator uses brakes on both treads at the same time in order to stop, but brakes on only one tread to turn the tank. By braking one side, the operator causes that side to slow down or stop while the other side continues at the previous speed, causing the tank to turn towards the slower tread. 
Story: Benjamin is taking an Army training class and is learning to operate a tank. Today, he is in a tank with an instructor on a training course. Benjamin drives the tank forward and comes to a large dirt mound blocking his path. He needs to decide whether to break the left tread or right tread.                                 
                                                   Eric is operating a tank in a war zone.  The battlefield is filled with large debris and needs to be navigated carefully. A large wall is blocking Eric's way forward and his right side. 
Question: Which tread should Eric slow to avoid the wall?
Output (English): left.