The correct answer is letter D: firefighting brigades. The first brigade was created by Marcus Licinius Crassus who, together with 500 men, would run to burning buildings and bargained their way in, in exchange of putting out the fire. If the owner of the place refused to pay what they were asking for, they'd just leave the place burn to the ground. After that, Emperor Nero built a force that used to patroll the streets of Rome and that's basically how the Roman Empire created the world's first firefighting brigade.