5. (6 points) Assume the market price for a share of a common stock is $100. An investor buys a put option at a strike price of $100. The option premium is $400. If the market price of the stock goes down to $80 per share what is the profit or loss to the buyer of the put option? a. $-380 b. $380 C. $-1,600 d. $1,600