A because its asking something about probably the article instead of some that doesn't mean anything
<span>A.
Half the students were failing the course near the end of the school year.
The sentence is written in passive voice because the course is the subject of the sentence and was being failed is the main verb phrase. The course can't fail. The students are the ones who are failing so to change it you must make the students the subject of the sentence. A is the only option that makes the students the subject.
</span>
The first president of Brazil was <span>Fernando Henrique Cardoso who became the first president of Brazil in 1998.</span>
