Ajay wants to read a brief overview about early settlers in the United States. Which type of online text source should he most likely use?

a blog

an e-book

an e-zine

an online reference

An e-book would be best. This would be the most authoritative source for events that took place in the early US, from a historical perspective. The other three sources listed could be fraught with (un-) intentional biases and unverified propositions that would not be of any academic use.