How Is the Bargain Element for a Stock Option Calculated

How is the bargain element for a stock option calculated?

A) The difference between the strike price and the market price on the date of grant.
B) The difference between the market price on the exercise date and the market price on the date of grant.
C) The difference between the market price on the exercise date and the strike price.
D) The difference between the market price on the sale date and the strike price.The bargain element is simply the difference between the market price on the exercise date and the strike price.