You Started a New Business and Your Twin Sister Helped

You started a new business and your twin sister helped you out for free while she turned down a project that would have paid her a total of $200.When calculating the costs involved in starting up the new business,you should

A) not include $200 since you did not have to pay your sister.
B) include $200 as the sunk cost.
C) include $200 as an average weekly cost since this is what your sister might have received.
D) include $200 as the opportunity cost of your sister's labour.
E) not include your sister's labour since she is family.