关于EDI的描述错误的是( )。

A．EDI信息的最终用户通过计算机应用软件系统自动处理传递来的数据

B．EDI是一种数据交换技术，是Electronic Data Interchange的简称

C．EDI技术仍然处于起步阶段

D．利用计算机与通信网络来完成标准格式的数据传输，传输渠道中无人工干预

You are the project manager for software development project. The feasibility study can start any time and takes 1 week and requirement gathering takes 2 weeks which can start only after feasibility study. The design and test plan development can start in parallel after the requirements gathering. Test plan preparation takes 8 weeks followed by a review by the customer and the time estimated for review is 1 week. After the review, Test data preparation takes 6 weeks. Design takes 6 weeks and it is followed by development and unit testing, for one module it takes 2 weeks and for the other module it takes 2 weeks. There are no dependencies between modules and they can be developed simultaneously. After test data preparation and development and unit testing of both the modules, there is 2 weeks system testing. What is duration of the critical path ？（）

A．14 weeks

B．15 weeks

C．20 weeks

D．19 weeks