Final answer:
The profit at maturity of the long call would be $10. Therefore, the correct option is B.
Step-by-step explanation:
The profit at maturity of a long call bought at $10 with a strike price of $100, when the underlying asset price is $120, can be calculated as follows:
Profit = Maximum (0, Asset price at maturity - Strike price) - Premium paid
Profit = Maximum (0, $120 - $100) - $10 = $20 - $10 = $10
Therefore, the profit at maturity of the long call would be $10.