$17.$ Suppose you purchased $1000$ shares of ABC common stock at $$19$ with an initial margin of $50\%.$ At a maintenance margin of $\_\_\_\_\_\_\_\_\_\_\_$ you received a margin call when the stock price falls to $$13\mathrm{.}57.$ What? $($Assume the stock pays no dividend; ignore interest on margin$)$

Question $6$Select one:

a$.$

$35\%$

b$.$

$40\%$

c$.$

$33\%$

d$.$

$30\%$