The correct answer is B. Roger's quick thinking prevented a serious accident on the highway.
Explanation:
In language, the active voice occurs when the subject of the sentence directly acts. In terms of grammar, this can be identified because the sentence presents the subject, then the verb and finally any object or complement if necessary. On the opposite, in the passive voice the emphasis is the actions and the object or complement, because of this, the object is first presented, then the verb (auxiliary verb followed by past participle) a finally the subject although this can be omitted.
Considering this, from the options presented the only sentence that is written in active voice is " Roger's quick thinking prevented a serious accident on the highway", because in this the subject if firs presented (Roge'rs quick thinking), then the verb (prevented) and finally the object (a serious accident) which means the subject directly performs the action and there is an emphasis on it. Also, other options contain the verb form "was prevented" that belongs to the passive form of "prevented" and therefore the verb form also indicates active voice.
