--You are leaving your school. How do you like it?

--Very much, of course, I ______ this school since I moved here.[ ]

A. came to

B. have gone to

C. have been to

D. have been at

技术可行性研究是根据客户提出的系统功能、性能要求及实现系统的各项约束条件，从（）的角度研究实现系统的可行性。