At time $=0$ you buy a call option on IBM for R $12\mathrm{.}50.$ The option gives you the right to buy $100$ shares of IBM stock at time$=$T at R$120.$

$(4)$

a$.$ What is the profit$/$loss to you if $ST=R85?$

b$.$ What is the profitloss for the writer if $ST=R90?$

c$.$ What is the profit$/$loss to you if $ST=125?$

d$.$ What is the profit$/$loss for the writer if $ST=R130?$