Visa (for a conference in China) for Malaysia Passport Holder- Business M?

Hi. I plan to visit Nanjing and Ta'ain at the end of August for attending a conference. My questions are (1) Do I need a business M? (2)I am flying from Malaysia (or perhaps from Amsterdam) to Nanjing, then to Ta'ain via train, then back to Malaysia (or Amsterdam). Do I need a single entry or multiple entry visa? Thanks.