 Complete the following phrase:  Unable to push north into the Netherlands, the Allies in western Europe were forced to consider other options to get into Germany. In the summer of 1944, the Allies suffered from a large supply crisis, due to the long supply route. But by the fall of 1944, this had largely been resolved by the Red Ball Express. As part of the Siegfriend Line Campaign, the Allies tried to push into Germany towards the Rhine. As a first step, Aachen was captured during a 