Question: 7/7 Ripple Effect is a 57-minute homemade film produced and narrated under the pseudonym "Muad'Dib", the film disputes the official account of the 7 July 2005 London bombings (also known as 7/7), a terrorist attack on public transport in Central London, by four suicide bombers, including Germaine Maurice Lindsay, also known as Abdullah Shaheed Jamal, was one of the four terrorists who detonated bombs, on how many trains?
Answer: three