问题详情

It can be inferred from paragraph 2 that before the visa regulations were revised foreign teachers didn"t have to ______.
A．sign new contracts if they wanted to continue to work.
B．go through any formalities if they wanted to stay a bit longer.
C．visit a neighboring country if they wanted to renew their visas.
D．interview a South Korean official if they wanted to apply for work permits.请帮忙给出正确答案和分析，谢谢！