The following sentence is in the active voice: "She sings a song....
B) She is sung beautifully.
In the passive voice, the object of the active sentence becomes the subject of the passive sentence, and the verb is changed to a form of "to be" + past participle. In this case, "she" is the object of the active sentence, so it becomes the subject in the passive sentence. The verb "sings" is changed to "is sung" in the passive voice. The adverb "beautifully" stays in the same position in the sentence.
The following sentence is in the active voice: "She sings a song....
Is - v1 and sung - v3 will never come together in a sentence. All the answers are wrong to be a passive voice. please avoid such blunders