Question

Based on your knowledge of word parts, which word best completes this sentence? Stephen's excellent performance in his French classes _____ him to try speaking only in French during his trip to Paris.

Answer 1

Correct answer 2.) emboldened

Encased refers to the idea that something is enclosed, which does not make sense to be enclosed when he is trying to speak French in Paris. 

Emboldened, the correct answer, means that you are bold and empowered to be bold. 

Ensnared implies that you are caught in something like a trap. 

And Encroached means an intrusion. In this case he did not intrude to speak French in Paris.