The answer is:
At age nine, students began learning Latin, which was the language of international affairs.
Relative clauses provide additional information about something that has already been mentioned. In this case, the subordinate relative clause "which was the language of international affairs," makes a further comment about the previously mentioned Latin language.
The play's villain, Iago, is the epitome of dishonesty and his untruthful nature is contrasted with the innocent Cassio and Desdemona. He uses his skills in deception to lie to almost every other character in the play in particular Othello, but also to Roderigo and Cassio.
Answer:
C should be the correct one
