Scanlon Inc.$\text{'}$s CFO hired you as a consultant to help her estimate the cost of capital. You have been provided with the following data: $r_{RF}=4\mathrm{.}10\%$;$RPM=4\mathrm{.}90\%$; and $b=0\mathrm{.}60.$ Based on the CAPM approach, what is the cost of equity from retained earnings?

a$.5\mathrm{.}40\%$

b$.7\mathrm{.}04\%$

c$.9\mathrm{.}00\%$

d$.7\mathrm{.}36\%$

e$.9\mathrm{.}60\%$