Which of these is appropriate concert behavior during live performances? opening noisy candy wrappersreceiving urgent callswalking down the center of the aisle with a video cameraavoiding flash photography during the performance

The last one -avoiding flash photography during the performance. 

The answer is to avoid flash photography during the performance because the performer might be distracted and/or might have eye problems

Generally spontaneous human combustion is something that still bewilders some, human combustion happens very rarely and doesn't affect the surrounding areas, so unless you want to set your self on fire, human combustion will remain spontaneous and very rare.