The US troop surge in Iraq in 2007 gradually decreased violence, as it is proved by the statistics of the war. Option B is correct.
During the Iraq War, the surge makes reference to United States President George W. Bush's 2007 rise in the number of American troops in an attempt to grant security to Baghdad along with Al Anbar Province.
Under Bush order, more than 20,000 soldiers were deployed into Iraq and sent most of them into Baghdad.