Answer:
Flashbulb memory
Explanation:
Flashbulb memory is the memory caused by an event which is significant in a person's life, through which they remember the environment they were in, the moment they were exposed to the event in exceptionally high detail.
September 11, 2001 was a day that shook the foundation of people as they had not experienced something like this anywhere in the world. Marcela was able to remember everything in vivid detail.
Hence, this case describes the phenomenon of flashbulb memory.