Answer:
$36
Step-by-step explanation:
First, you sold the stock short at $50, and then sold a put option and received $4 per stock. Since the strike price of the put option is $40, the basis of the stock will be $40 - $4 = $36. You had to purchase the stocks to cover your short sale, so your gain = $50 (proceeds from short sale) - $36 (net basis) = $14 per stock