A$.)$Create a user$-$defined function in EXCEL to calculate the value of a common stock using the earnings model that was introduced in Chapter $9$ on page $284.$ B$.)$What arguments will you need to accept in order to implement equation $(9-13)$ exactly as it is displayed? $($Picture of equation $9-13$ is attached$)$ C$.)$Now change your function so that it requires the retention ratio, instead of the expected retained earnings.