Final answer:
The sentence written in passive voice among the given options is c) The van was driven to school by Jack. This is because the subject 'the van' is acted upon by the doer 'Jack', indicated by the use of the 'be verb' was with the past participle 'driven', and the presence of the preposition 'by'.
Step-by-step explanation:
When trying to identify sentences written in passive voice, several key characteristics should be examined. First, determine if the subject of the sentence is the recipient of the action rather than the doer. In passive sentences, the action is performed on the subject, as shown in the example, "The van was driven to school by Jack." This structure indicates that the van is receiving the action done by Jack.
Second, look for a form of the be verb (am, is, are, was, were) appearing alongside the past participle form of the main verb. In the sentence "The van was driven to school by Jack," 'was' is the verb used with the past participle 'driven.' Lastly, a passive sentence may include or imply the preposition 'by.' In your options, the only sentence matching all these criteria of passive voice is c) The van was driven to school by Jack.