C210
In fact, he didn't know when Yan Guimei and Meng Yuloong died, but he remembered Yan Guimei entering and leaving the university campus when she was about 17 or 18 years old. She just happened to see someone confess to Meng Yuloong, which meant that she didn't know what was wrong with Meng Yuloong.
Naturally, Meng Yuloong didn't respond. He didn't agree or reject Yan Guimei