He works more diligent now that he had become vice president of the company?

1. A Option A: He works more diligent now that he had become vice president of the company.
2. B Option B: He works more diligently now that he has become vice president of the company.
3. C Option C: He began to work more diligent now that he had become vice president of the company.
4. D Option D: He worked more diligently now that he had became vice president of the company.

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