Find the sentence written in the active voice:

In an active voice sentence, the subject performs the action of the verb. In Option B, 'He' (subject) is performing the action 'cleaned' (verb) upon 'the car' (object).

Step-by-step Derivation:
Step 1: Analyze Option A ('The car has driven by him'). This is a grammatically incorrect attempt at passive voice. In passive voice, the object becomes the subject; however, 'has driven' is active form, while 'by him' suggests passive. The correct passive would be 'The car has been driven by him'.
Step 2: Analyze Option B ('He cleaned the car'). The subject is 'He', the verb is 'cleaned', and the object is 'the car'. The subject is the doer of the action. This fits the definition of active voice (Subject + Verb + Object).
Step 3: Analyze Option C ('It will be more complex algorithm'). This is a descriptive sentence using a linking verb ('will be') to describe a state or quality. It does not involve a transitive action performed by a subject on an object, and thus is not an example of active voice in the context of action verbs.
Step 4: Conclusion: Option B is the only grammatically correct sentence where the subject actively performs the action.