Explain whether the following statements are true, false, or uncertain:

(a) There is no difference between the central bank selling 100 m. of securities to an individual and a commercial bank with regard to the effects on the monetary base. (b) When government has budget deficit, it will lead to trade deficit at the same time.

(c) The adverse selection (lemons) problem would be more severe for stocks traded on the New York Stock Exchange or those trade in over-the-counter-market in the United States.

(d) Under the current situation of Covid-19, money demand will decrease.