What is a flashback?

a. an object or sensory experience that triggers memories
b. a device in which the story opens and ends in the same moment
c. a point in the story that shows something that happened earlier
d. a sudden moment of realization or change for a character

"night. no one was praying for the night to pass quickly. the stars were but sparks of the immense conflagration that was consuming us. were this conflagration to be extinguished one day, nothing would be left in the sky but extinct stars and unseeing eyes." explain the images included in the passage. how is the use of the image of night contradictory to how we might expect it to be used