$13.$ Last year, you earned a rate of return of $8\mathrm{.}13$ percent on your bond investments. During that time the inflation rate was $3\mathrm{.}68$ percent. What is your real rate of return?a$\mathrm{.}4\mathrm{.}29$ percentb. $4\mathrm{.}45$ percentC$\mathrm{.}10\mathrm{.}62$ percentd. $11\mathrm{.}81$ percente. $12\mathrm{.}11$ percent