You short $100$ shares of TEMA stock when it is selling at $$100.$ Your broker for this transaction imposes an initial margin requirement is $100\%.$ You have cash to put down only $60\%$ of the short sale value. Your broker lets you borrow the remaining $40\%$ due to past relationship between the two firms. The commission on the sale is $0\mathrm{.}5\%$ of transaction amount. Your broker$$s maintenance margin is $25\%.$

$($a$)$ At what price of stock will you receive a margin call from your broker?

$($b$)$ TEMA shares rose to as much as$$130$ per share due to a good news announced by management. How much additional money must you deposit to bring the current margin to your broker$$s maintenance margin?

$($c$)$ You decide to buy back shares at $$90$ to cover your short position at the end of one year. What is the ROIC for this transaction? You pay a commission of $0\mathrm{.}5\%$ again on closing. While you are short, TEMA paid a $$0\mathrm{.}5$ per share dividend. Your broker charges a $10$ percent interest rate.

$$ please show work and explain