Final answer:
The color of the streamer attached to an automatic parachute with a 4 to 5 second delay cartridge is yellow. This color coding corresponds to the use of a solid fuel mixture in the engines that fire at 4 seconds.
Step-by-step explanation:
The color of the streamer that is attached to the back automatic parachute with a 4 to 5 second delay cartridge is yellow. This color coding is associated with the use of a solid fuel mixture, as referenced by the information stating that engines firing at 4 seconds with a yellow flame are using a solid mixture. This is in contrast to engines that fire at 3 seconds which display a green flame and use a liquid fuel/oxidant mixture.