In your situation, a single entry business visa is enough. The visa should be processed in May or June because single entry China is valid for 3 months from issue date. For Business visa application, you need to bring to the Chinese embassy your original passport and copy of personal information page; application form for China V2011A; one passport-sized photo stuck to the application form; invitation letter from the inviter Center, and sometimes, you may asked to provide an invitation letter issued by local foreign affairs office if necessary.
You can submit your application in person or entrust a third party to submit your application on your behalf to the visa office of Chinese Embassy in the Netherlands. In principle, the normal visa processing time is 4 working days.