Assume That Long-Term Corporate Bonds Had an Average Return of 6.4

Assume that long-term corporate bonds had an average return of 6.4 percent and a standard deviation of 2.9 percent for a 50-year period.What range of returns would you expect to see on these bonds 68 percent of the time?

A) 3.5 percent to 9.3 percent
B) 3.5 percent to 10.9 percent
C) 2.9 percent to 6.4 percent
D) .6 percent to 11.9 percent
E) .6 percent to 12.2 percent