根据提示回答下面问题。

1. How does he go to work? (subway)

    ______________________________________________

2. What does he do? (actor)

    ______________________________________________

3. Excuse me, where is the library?  (post office, next to)

    ______________________________________________

4. Where are you going this weekend?  (the Great Wall)

    ______________________________________________

5. What's your hobby?  (read a book)

    ______________________________________________

（）扮演着买卖双方签约、履约的监督管理角色，买卖双方有义务接受其监督管理。

A.网络交易中心

B.政府监管部门

C.第三方认证中心

D.网络银行