You are currently evaluating CVS stock with a current price of $27\mathrm{.}5$ you would like to buy $30$ shares of this stock on margin at $65\%$ and maintain a $55\%.$ If the stock price drops below blank you will get a margin call a $21\mathrm{.}39$B $11\mathrm{.}5339\mathrm{.}72$D $6\mathrm{.}2.$