The correct option is B Conventional teaching methods are not used by us.
<!--td {border: 1px solid #cccccc;}br {mso-data-placement:same-cell;}-->
The correct answer is ‘Conventional teaching methods are not used by us.’ In the given sentence, the focus is on the doer, ‘We’ because the doer is actively performing the action on ‘the receiver’, conventional teaching methods. When we change the sentence into passive voice, the focus shifts from ‘the doer’ of the action to ‘the receiver’ of the action, that is, ‘conventional teaching methods.’