Debra Diacono, CFO of Rivers Ltd a listed Australian company, has approached you for advice on how to estimate the companys weighted average cost of capital. She supplies you with the following information to assist you with your calculations:$13-$week Treasury note yield $3\mathrm{.}00\%$ p$.$a$.,10-$year government bond rate $3\mathrm{.}50\%$ p$.$a$.,$Number of Rivers Ltd shares on issue $10$ millionCurrent share price $$45\mathrm{.}60$Bond details:One thousand $6\%$ fixed$-$rate bonds with a face value of $$100,000$ each initially issued with $10$ years to expiry $4$ years ago. Coupons are paid annually with one full year until the next coupon is paid$\mathrm{.}10-$year bonds with the same credit rating are currently being issued with coupon rates $=5\mathrm{.}5\%$ p$.$a$\mathrm{.}6-$year bonds with the same credit rating are currently being issued with coupon rates $=4\mathrm{.}5\%$ p$.$a$.$Corporate tax rate $30\%,$Market risk premium $7\%$ p$.$a$.,$Standard deviation of returns on the ASX $20025\%$ p$.$a$.,$Standard deviation of returns on Rivers Ltd shares $30\%$ p$.$a$.,$Covariance between the returns on the ASX $200$ and Rivers Ltd shares $0\mathrm{.}045($a$)$ Calculate the cost of equity capital for Rivers Ltd$.($b$)$ Calculate the $($after tax$)$ cost of debt capital for Rivers Ltd$.($c$)$ Calculate the after$-$tax weighted average cost of capital for Rivers Ltd$.[$hint: when calculating the market value of the bonds, make sure you follow the market convention and use the relevant market yield for those bonds quoted on a before$-$tax basis$]$