According to the market segmentation theory, an upward sloping yield curve is most likely due to:（）

A. investor expectations that short-term interest rates will rise in the future.

B. different levels of supply and demand for short-term and long-term funds.

C. an increasing yield premium required by investor for bearing interest rate risk.

表演游戏中最为常见的是（），它是以故事、诗歌等文艺作品为蓝本，由幼儿按自己对作品的理解，在游戏中自编自演。