If real money balances are $1,000 billion (2021 dollars), and the monetary expansion rate is 20%, what is the annual rate of seigniorage (in billions of 2021 dollars per year)? (Assume the government creates the entire money stock directly and ignore the growth of the economy). a) $20 billion b) $200 billion c) $1,000 billion d) $5 trillion e) $50 trillion