以硅胶为固定相的薄层色谱通常属于

A．分配色谱

B．吸附色谱

C．离子抑制色谱

D．离子交换色谱

E．离子对色谱

An analyst identifies the following cash flows for an average-risk project: Year 0 - $ 5000 Years 1-2 $ 1900 Year 3 $ 2500 Year 4 $ 2000 The project’s discounted payback period if the company’s cost of capital is 12% , and internal rate of return of the project, are closest to: Discounted payback periodIRR （）

A. 3.0 years           13.3%

B. 3.0 years           23.2%

C. 3.9 years           13.3%