<u>Which sentence is written in the active voice? </u>
<em>C) Anrea's Heating and Air Company will install the ventilation system. </em>
<u>Active voice</u> presents a subject doing an action, whereas <u>passive voice </u>focuses on the action that the subject does, switching the direct object and the verb tense (<em>"the ventilation system"</em>).
The remaining sentences are written in passive voice. For example, <u>Sentence C </u>written in a passive voice would be:
<u><em>The ventilation system</em></u><em> </em><em>will be installed by</em><em> Anrea's Heating and Air Company. </em>