Australia uses "distant learning" methods,____ the students ……

题目

Australia uses "distant learning" methods,____ the students ……
请问：
Australia uses "distant learning" methods,____ the students have lessons by two-way radio and mail.
A which B where C that D when
为什么答案选B 是个什么从句?怎么翻译?

答案

这里的where从句是修饰Australia的,
澳大利亚采用“远程教学”法,那里的学生用两种方式学习---收音机和邮件.