risk-free rate

You read in the Wall Street Journal that 30-day T-bills are currently yielding 8%. Your brother-in-law, a broker at Kyoto Securities, has given you the following estimates of current interest rate premiums:
Inflation premium 5%
Liquidity premium 1%
Maturity risk premium 2%
Default risk premium 2%Based on these data, the real risk-free rate of return is
a. 0%
b. 1%
c. 2%
d. 3%
e. 4%