Answer:
B) Secondary sources
Step-by-step explanation:
primary sources are from someone living at that time / someone who directly experienced the event they are talking about
secondary sources are people [who did not experience the event] writing about an event after it occurred. These people were not directly involved in the event, making them secondary (you can think of it as second-hand information) sources.
tertiary sources are essentially sources identifying primary / secondary sources (they're a reference for resources)