A stock you are holding has a beta of $2\mathrm{.}0$ and the stock is currently in equilibrium. The required rate of return on the stock is $15\%$ versus a required return on an average stock of $10\%.$ Now the required return on an average stock increases by $20\mathrm{.}0\%($not percentage points$).$ The risk$-$free rate is unchanged. By what percentage $($not percentage points$)$ would the required return on your stock increase as a result of this event?

Select the correct answer.

a$.26\mathrm{.}55\%$

b$.26\mathrm{.}71\%$

c$.26\mathrm{.}63\%$

d$.26\mathrm{.}59\%$

e$.26\mathrm{.}67\%$