Answer:
The excerpt from "War Message to Congress" which expresses President Wilson's opinion is:
A. Each nation must decide for itself how it will meet it.
Step-by-step explanation:
First, let's take a look at options B through D. They all state facts, that is, something that is known or that can be proved to be true. It is a fact that something was said on the 3rd of February. It is a fact that ships were sunk by submarines. It is also a fact that people died in such attacks. Now, when we take a look at option A, we can easily see that it expresses an opinion, not a fact. It is President Wilson's opinion that each country must make a decision for itself. Other people may disagree with him, saying, for instance, that nations should make a collective decision. Thus, we can safely choose letter A as the option that expresses an opinion.