Final answer:
Short selling the overpriced puts, as they are priced higher than the valuation from Black-Scholes and put-call parity indicates, allows for a risk-less profit.
Step-by-step explanation:
If you determine that put options should be priced at $1.00 using Black-Scholes and put-call parity, and they are currently priced at $2.00, the correct course of action would be short selling the puts. This is because the puts are overpriced according to your valuation and this presents an opportunity for a risk-less profit.
Put-call parity ensures that the pricing of calls and puts with the same strike price and expiration must be consistent with each other. Therefore, if the calls are fairly priced, the puts should also be correctly priced, assuming no arbitrage opportunities. Since this is not the case, the overpriced puts provide a clear signal for short selling.
Since the puts should be priced at $1.00 instead of $2.00, it indicates that the puts have higher implied volatility than the calls. Implied volatility measures the market's expectation of future volatility in the underlying stock.