A strategy consists of buying a market index product at $830 and longing a put on the index with a strike of $830. If the put premium is $18.00 and interest rates are 0.5% per month, what is the profit or loss at expiration (in 6 months) if the market index is $810?
$18.65 gain
$20.00 gain
$36.29 loss
$43.76 loss