Passive maybe I don't know that word but yeah
The correct answer is one main clause.
This means that there is only one verb in the sentence, which in this case is the verb 'was.' Even though drive is also a verb, in this context it is used as an adjective driven (participle form of the verb to drive) and is thus not considered to be a verb. This means that there are no subordinate clauses but rather just one main clause.
Based on the genre, (let’s take fantasy for example) you can get inspiration from fairytales, creatures, history, or your imagination. Mostly your imagination can help you with coming up with ideas :)