I think it’s D!
In a sentence using passive voice, the subject is acted upon; he or she receives the action expressed by the verb. The agent performing the action may appear in a "by the..." phrase or may be omitted. The dog is acting upon the sentence subject (the boy), meaning it uses the passive voice.
I believe that Faustus originally asked Mephastophilis to bring him Helen of Troy because he lusted after Helen and wanted to possess her.
Helen is the symbol of ultimate beauty, and his hedonistic side wanted to indulge his more primal needs.
The answer for your question is B: Formal
Appoint means to assign something such as a job.
For example:
-Jack was appointed prime minister last year.
Hope it helps