Which one of the following statements is true regarding the period 1926-2014?

a.

The inflation rate was just as volatile as the return on long-term bonds.

b.

Bonds had an average rate of return that exceeded the average return on stocks.

c.

The risk-free rate of return remained constant over the time period.

d.

U.S. Treasury bills had a positive average real rate of return.

e.

The returns on small-company stocks were less volatile than the returns on large-company stocks.