$(18).$ You purchased $150$ shares of Wal$-$Mart stock on margin for $$50$ per share $($you put in the minimum amount of cash allowed$).$ The initial margin is $40\%$ and the maintenance margin is $30\%.$ Below the stock price of $\_\_\_\_\_\_\_\_\_\_,$ you would get a margin call. Assume the stock pays no dividends and ignore interest on margin.

$($a$)$ $$42\mathrm{.}86$

$($b$)$ $$43\mathrm{.}85$

$($c$)$ $$40\mathrm{.}85$

$($d$)$ $$41\mathrm{.}86$

$($e$)$ $$44\mathrm{.}50$