请教各位学霸英语语法问题

请问应该选择哪个？属于什么语法？
The petroleum company has challenged the claims of environmental___ the oil spill is responsible for the destruction of the animals' habitat.
A. groups, that
B. groups that
C. groups, which
D. groups whom
一看到这种语法题就发懵，麻烦各位大神江湖救急！！

B. That引导claims的同位语

B. That引导claims的同位语

谢谢谢谢！！厉害