Final answer:
The adjective 'Resigned' best describes Matt's expression indicating acceptance of his lack of success.
Step-by-step explanation:
The student's question requires the selection of an adjective that best describes Matt's expression, based on the context provided. Among the options A) Detached B) Resigned C) Fenced D) Withered, the most fitting choice would be B) Resigned. This adjective indicates that Matt has accepted his lack of success without protest, which aligns with the context given, suggesting an acceptance of a negative situation with a degree of submission or helplessness. The other options do not accurately convey the sentiment implied in the phrase "he wasn't having much success," as they do not denote the same sense of acceptance in the face of difficulty or the implication that Matt has given up trying to succeed.