If the discount factor is $0\mathrm{.}9,$ what will be the net present value $($NPV$)$ of the income? Show the full equation of NPV from year $0$ to $5.[$Hint: discount factor $=11,$ where r is the discount rate. To calculate NPV using excel, use the r value.$](10$ Points$)$ b$)$ What will be value of internal rate of return $($IRR$)?(10$ Points$)$ c$)$ Suppose we know the utility function of this individual, where utility at any year t is $=(50,000+)12$ and $$ is the income of this individual at year t $,$and t$=0,1,2,3,4,$ and $5.$ How would your calculation of a$)$ and b$)$ change with this new information? $(20$ Points$)$