you purchase $200$ shares for $$50$ a share, and after a year the price rises to $$70.$ what is your percentage return if you bought the stock on the following margin: a$.50\%($ignore commissions, dividends, and interest expense$)$ b$.30\%($ignore commissions, dividends, and interest expense$)$ c$.20\%($and the borrowing cost was $10\%$ of initial purchase$).$