单选题：根据材料，回答题。Until I took Dr Offutt's class in DeMatha High Scho

根据材料，回答题。Until I took Dr Offutt's class in DeMatha High School, I was an underachieving student, but I left that class (31) ___ never to underachieve again. He not onlytaught
me to think, he convinced me, (32)__ by example as words that it was my moral (33)___ to do so and to serve others.
(34)___ of us could know how our relationship would (35) __ over the years. When I came back to DeMatha to teach English, I worked for Dr Offutt, the department chair. My discussions with him were like graduate seminars in adolescent (36) ___, classroom management and school leadership.
After several years, I was (37) ___ department chair, and our relationship (38) __ again. I thought that it might be (39) ____ chairing the department, since all of my (40)___English teachers were (41)___ there, but Dr Offutt supported me (42)___ Fie knew when to give me advice (43)___ curriculum, texts and personnel, and when to let me (44)___ my own course.
In 1997, I need his (45) ___ about leaving DeMatha to become principal at another school. (46)___ he had asked me to stay at DeMatha, I might have. (47)____, he encouraged me to seize the opportunity.
Five years ago, I became the principal of DeMatha. (48) ____, Dr Offutt was there for me, letting me know that I could (49) __ him. I've learned from him that great teachers have an inexhaustible (50)__ of lessons to teach._________填上最佳答案。 A．concerned
B．worried
C．determined
D．decided