There is a new problem _____ in the popularity of private cars _

There is a new problem _____ in the popularity of private cars _____ road conditions need to be improved.
A、involving ; that
B、involved ; that
C、involved; where
D、involving ; which
【正确答案】：B
【题目解析】：be involved in被卷入...中，涉及到....；that引导同位语从句，作problem的同位语，解释problem的具体内容。