The correct answer is C because the payoff to the call buyer at expiration is calculated as the maximum of zero or the difference between the underlying asset's price (St) and the strike price (X). Given the call option's value at expiration is $17.80, we solve for St: $17.80 = Max(0, St - $130). This simplifies to St = $130 + $17.80 = $147.80.

• Option A is incorrect as it assumes the payoff formula for a put option, leading to St = $130 - $17.80 = $112.20.
• Option B is incorrect as it adds the option's profit (value at expiration minus purchase price) to the strike price, resulting in ($17.80 - $5.75) + $130 = $142.05, which does not represent the underlying asset's price.