Final answer:
The correct word to complete the sentence about Jackson's reaction to his ceramic piece exploding in the kiln is 'resolve'. This shows his determination to learn from the experience and improve.
Step-by-step explanation:
The word that correctly completes the sentence is resolve. So the sentence should read: "But then slowly, his frustration was replaced with resolve. He'd use what he learned from making that piece to create an even greater masterpiece!" The choice of this word helps to convey the idea that Jackson is taking his disappointment and using it as motivation to succeed in the future. This positive turn illustrates a theme that is common in narratives of personal growth and learning from failure.