Select the correct passive form of the given sentence.

She is teaching French to children.

Children are being taught French by her.

The correct passive form of the given sentence is Children are being taught French by her.

The active voice of the sentence is She is teaching French to children. This sentence is in the present continuous tense, which is used to describe an action that is happening now. The passive voice of the sentence is formed by putting the subject of the active sentence after the verb "to be" and the present participle of the main verb. In this case, the subject of the active sentence is "she" and the main verb is "teach." The present participle of "teach" is "teaching." So, the passive form of the sentence is Children are being taught French by her.

The other options are incorrect because:

• Children have been taught French by her. is in the present perfect tense, while the original sentence is in the present continuous tense.
• Children were taught French by her. is in the simple past tense, while the original sentence is in the present continuous tense.
• Children are taught French by her. is in the active voice, while the question is asking for the passive voice.