In options markets, the method of settlement—whether based on a point-in-time price or a time-weighted average—can meaningfully impact pricing, risk, and the potential for manipulation. To explore this, we conducted a Monte Carlo simulation of 100,000 price paths for a 30-day ATM BTC call option under multiple settlement schemes: European (spot price at expiry), and Asian-style TWAP over 30-, 60-, and 120-minute windows. The objective was to measure how option valuation changes as the averaging window expands and to assess how TWAP-based settlement reduces exposure to manipulation while introducing pricing deviations. Results showed that the European option consistently priced higher, especially near expiration, due to its sensitivity to short-term volatility. At low volatility (σ = 0.1), the European-style option was overpriced by up to 2.75% relative to the 120-minute TWAP. In contrast, using a 30-minute TWAP window brought the overpricing down to just 0.60%, revealing a trade-off: longer TWAP windows reduce manipulation risk but also lead to greater divergence from fair value due to temporal averaging. These findings highlight the importance of settlement structure in options pricing and underscore how TWAP-based methods can mitigate risk while influencing price discovery mechanics.