单选题 Paul Ostrowski, CFA, is a well-known economist working of local government and does research about unemployment. Which of the following types of unemployment are included in the natural unemployment rate?
A. Structural and cyclical.
B. Cyclical and frictional.
C. Frictional and structural.

【正确答案】 C

【答案解析】[解析] 自然失业率是指充分就业下的失业率，不包括周期性失业(cyclical unemployment)，但仍然有摩擦性失业(frictional unemployment)和结构性失业(structural unemployment)。