俄国现实主义文学的奠基人是（）。

Many of the activities performed during the preliminary investigation are still being conducted in （）, but in much greater depth than before. During this phase, the analyst must become fully aware of the （） and must develop enough knowledge about the （） and the existing systems to enable an effective solution to be proposed and implemented. Besides the （） for process and data of current system, the deliverable from this phase also includes the （） for the proposed system.

Many of the activities performed during the preliminary investigation are still being conducted in （）, but in much greater depth than before.

A．analysis phase

B．design phase

C．implementation phase

D．maintenance phase