A sentence is in the passive voice, on the other hand, when the subject is acted on by the verb. The passive voice is always constructed with a conjugated form of to be plus the verb's past participle. Doing this usually generates a preposition as well.
The correct answer to this
question is:
<span>a.
</span>On your back with a pillow under your body.
It helps to put a pillow under your body to support your
back. This is one way of practicing to erecting your posture.