Engler Corporation's stock had a required return of $9\mathrm{.}50\%$ last year when the risk$-$free rate was $2\mathrm{.}50\%$ and the market risk premium was $5\mathrm{.}00\%.$ Then an increase in investor risk aversion caused the market risk premium to rise by $1\%$ from $5\mathrm{.}00\%$ to $6\mathrm{.}00\%.$ The risk$-$free rate and the firm's beta remain unchanged. What is the company's new required rate of return?

a$.10\mathrm{.}40\%$

b$.10\mathrm{.}90\%$

c$.11\mathrm{.}80\%$

d$.12\mathrm{.}50\%$

e$.13\mathrm{.}50\%$