I suggest Wikipedia and History.com. History.com would be more reliable and trustworthy.
The correct options are "premeditated invasion" and "grave danger".
We refer to words such as "invasion" and "danger" as loaded words because of how immediately they stick on our mind as we hear or read them inside a phrase. This occurs because the connotation and literal meaning of them is without a doubt negative, and represent very quickly the sense of a harming threat.
Hope this helps!
Answer NOT needed is description of the sentence
a topic sentence is needed to tell what you are writing about
proper capitalization, punctuation and spelling is always required
supporting details - needed to support your topic sentence
A. for .. the dao in the sapa area is famous for its “love market”
