$6-$You recently purchased $700$ shares of a stock for $$21$ a share using initial margin of $40\%.$ You sell the shares for $$25$ after some time, what is the return on your investment?

a$)50\%$

b$)47\mathrm{.}62\%$

c$)100\%$

d$)55\mathrm{.}56\%$

e$)33\mathrm{.}32\%$