The correct answer is C. Consider
Explanation:
A source is any material, document or similar including texts, videos, audio recordings, photographs or web pages used to know and understand a certain event. Because of this, sources are used for multiple purposes in different fields including history in which sources are used to get more information about an event, understand its causes and consequences, among others, etc. In this case, it is especially important to consider or include multiple sources and ideally look for different types of sources as this guarantees the information is reliable and therefore objective and historically accurate, especially because in history it is common to find sources that seem contradictory in relation to some event. Therefore, it is important to "consider" multiple sources for historical accuracy.
