Final answer:
The synonym for 'decisive' is 'Conclusive' as both terms refer to something that is definitive and clear-cut. The correct option is D.
Step-by-step explanation:
The synonym for "decisive" is d. Conclusive. Both words imply that something produces a final result or is definitive in nature.
A decision or outcome that is decisive is clear-cut and leaves no room for doubt, just as something that is conclusive definitively ends or resolves a debate or question.
Neither 'Faulty', which means incorrect or lacking, 'Expose', which means to reveal or uncover, nor 'Dedication', which relates to commitment or devotion, are appropriate synonyms for 'decisive'.