What were the long term causes of 9/11

The September 11 attacks (also referred to as 9/11) were a series of four coordinated terrorist attacks by the Islamic terrorist group al-Qaeda against the United States on the morning of Tuesday, September 11, 2001.The War on Terror, also known as the Global War on Terrorism, is an international military campaign that was launched by the United States government after the September 11, 2001 terrorist attacks against the United States.On the day of 9/11, the Taliban foreign minister told the Arab television network Al Jazeera: "We denounce this terrorist attack, whoever is behind it." The United States requested the Taliban to shut down all al-Qaeda bases in Afghanistan, open them to inspection and turn over Osama bin Laden.

im pretty sure the answer is b, i hope i < 3