An article by an economist at the International Monetary Fund about the shadow banking system notes:
As long as investors understand what is going on and such activities do not pose undue risk to the financial system, there is nothing inherently shadowy about obtaining funds from various investors who might want their money back within a short period and investing those funds in assets with longer-term maturities.

a. What kind of funding is the author referring to that is obtained from “various investors who might want their money back within a short period”? What kind of investors are involved?
b. What type of problems did this funding cause during the financial crisis? Did investors “understand what is going on” during that period? Briefly explain.