context: The hijackers were 19 Al-Qa'ida terrorists under the command of Osama bin Laden [5] and Khalid Sheikh Mohammed. [6] Studies have shown that the collapse of WTC dual towers is attributed to structural damage and fire caused by airplane collisions. [7] The collapse of WTC 7, in turn, was the result of fires that caused structures to fail. [8]
question: Which terrorist organization was behind the 9/11 attacks?
answers.text: Al-Qa'ida