Use reasoning to lead to the answer of the following question:
The man was happy to be seeing his idea become a reality, and knew his father would be proud, what did he feel in himself?\nOptions:\n- fulfilling\n- pain\n- excitement\n- inspiration\n- manual
 Reasoning process:
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As the man knew that his father would be proud, he feels fulfilling in hiself. The man was happy and feels fulfilling by seeing that his idea become a reality. Therefore, the final answer is fulfilling.
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