Dorothy was always speaking highly of her role in the play, ______, of course, made the others unhappy.

A. who

B. which

C. this

D. what

请结合给定资料，以“三心”为主题，自拟题目，自选角度，写一篇议论文。
要求：
1．主旨明确，内容充实，论述深刻。
2．结构完整，条理清晰，语言流畅。
3．字数1000～1200字。