Correct Answer: New ways of treating obesity are being learnt by Rabya.

Solution : The correct choice is the third option.

Passive voice is the voice in which the object experiences an action rather than the person who acts. Hence, the object in the active sentence becomes the subject in the passive voice.

To convert this into the passive voice, we use a form of the auxiliary verb "to be" along with the past participle of the main verb. In this case, "are being learned" is the passive construction,

The structure of a passive voice sentence is: Object + passive verb construction + agent (optional).

Therefore, the correct answer is: New ways of treating obesity are being learnt by Rabya.