Translation:If we want to go to the US, we will need a visa
The second verb construction is in the future tense, as indicated by the TA in tuTAhitaji, and this sentence makes more sense with a noun marker before USA and plural tense of visa. The solution should be as follows: "If we want to go to the USA, we will need visas."
Update (Feb 2019) - It looks like the course developers have now fixed it, according to the given answer here.
I presume Marekani can be interpreted either way. Technically, America is a geographical (not political) term:
"a landmass in the western hemisphere that consists of the continents of North and South America joined by the Isthmus of Panama."
You need to report that when you have answered the question. (There is a report flag and then a choice about the audio.)
That way, it gets back to the course developers. Here it is only the other students reading your comments so that we can help each other understand the questions and answers.