He sat on his bed looking at his brother had his arms crossed and looked angry. A. thatB

问题补充：

He sat on his bed looking at his brother, had his arms crossed and looked angry.

A. that

B. whom

C. who

D. which

答案：

A. that

B. whom

(答案→)C. who

D. which

解析：通过分析句子结构，可知这是一个主从复合句，其中包含一个非限制性定语从句，that不能用于引导非限制性定语从句，故排除A，关系词在定语从句中作主语，且是人，故用who。