Answer:
The passage is a primary source because it was written by someone who witnessed the event. Pliny the Younger, the author of the letter, was an eyewitness to the volcanic eruption at Pompeii. This makes the account a firsthand, original source of information about the event as it occurred during that time. Primary sources provide direct evidence and insights into historical events, making them valuable for historians and researchers.
Step-by-step explanation: