单选题 Anthony Gleason owns a stock valued at $50 per share. Gleason buys a put option with a strike price of $50 for $3. At expiration of the put option, the stock is valued at $65 per share. The profit from Gleason"s portfolio insurance strategy is:

A、 $18.
B、 $3.
C、 $12.

【正确答案】 C

【答案解析】The option is out-of-the-money at expiration ( Max (0, X - S) ) and is, therefore, worthless. Gleason gains the $15 per share increase in the stock price but is out the premium for the option, leaving a gain of $12=( $65- $50- $3).