The answer to the question above would be that the sentence that is written in the active voice is the following one: The science director's assistant placed the order yesterday afternoon.
This sentence is written in the active voice because it includes the doer of the action denoted by the verb. It indicates that the science director's assistant is the one who placed the order. He/she is the one who acts upon the action denoted by the verb. That's why it is called active voice. On the contrary, the other examples are in the passive voice because in those structures the doer of the action (or agent) has been supressed to emphasize the action and not the person doing it. Because the subject is being "acted upon" (or passive), the sentences are said to be in the passive voice.
'The science director's assistant placed the order yesterday afternoon', is the only sentence that has been written in an active voice out of the choices given above. Therefore, the option B holds true.
Active voice can be referred to or considered as a language in which the sentence is structured in such a way that the noun receives actions. An active voice can always take a direct object in a sentence. It is completely in contrast to that of a passive voice.
In the sentence given above, it can be seen that the language is direct and the noun, or the subject, is the recipient of the action, or the verb, in the sentence. Thus, it can be concluded as an example of an active voice.
Therefore, the option B holds true regarding the significance of an active voice.
Learn more about an active voice here:
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