Suppose an investor buys a call option on 45,000 barrels of oil
with an exercise price of $51 per barrel and simultaneously sells a
put option on 45,000 barrels of oil with the same exercise price of
$51 per barrel. Her net payoff per barrel on these option contracts
is _____ if the market price per barrel is $49 and _____ if the
price per barrel is $55.