"D" is the best answer - as it was for every one of these challenges. The Canadian staff tried every way possible to maximize success on their six objectives at Vimy. Thousands of shells with the new "108" fuze cleared out large sections of German wire, opening the way for the attackers. The creeping barrage was likely the most important reason the Canadians were able to cross No Mans Land relatively easily, but men pouring through the tunnels were able to pop up and swarm the German Number One trench without warning. The 1st, 2nd and 3rd Canadian Divisions moved so quickly that many defenders were trapped inside their underground bunkers. They were not even aware the Canadians were attacking.