Based on the Greenwood and Shleifer $(2014)$ study about investors$$ expectations of stock market returns, answer the following questions.

a$)$ What data does the study use?

b$)$ What is the evidence for the validity of the data?

c$)$ What are the main findings?

d$)$ According to the rational explanations of predictability of the equity premium based on the dividend$-$price ratio, why do people put up with low stock market returns after a low dividend$-$price ratio?

e$)$ How does Greenwood and Shleifer$$s study undermine the rational explanations?