During the period 1990 to 2017 , the average yield on 3-month U.S. Treasury bills was 2.78%, the average inflation rate was 2.28%, the average yield on 30 -year Treasury bonds was 5.22%, and the average return on 30 -year Aaarated corporate bonds was 6.08%. The real risk-free short-term interest rate is Selected answer will be automatically saved. For keyboard navigation, press up/down arrow keys to select an answer. a 0.30% b 0.50% C 2.97% 4.76%