The correct answer is: B. transaction costs.
The Black-Scholes model is a mathematical model that calculates the price of a European call option. It is based on the following assumptions:
- The stock price follows a geometric Brownian motion.
- The interest rate is constant.
- The volatility of the stock price is constant.
- There are no transaction costs.
- There are no dividends.
The Black-Scholes model assumes that there are no transaction costs. This means that the price of a stock is the same whether you buy it or sell it. In reality, there are always transaction costs associated with buying and selling stocks. These costs can include commissions, fees, and slippage. Slippage is the difference between the expected price of a stock and the actual price at which you buy or sell it.
Transaction costs can have a significant impact on the price of a stock option. For example, if the transaction cost is 0.5%, then the price of a call option will be 0.5% higher than the price that would be calculated using the Black-Scholes model.
In conclusion, the Black-Scholes model assumes that there are no transaction costs. However, in reality, there are always transaction costs associated with buying and selling stocks. These costs can have a significant impact on the price of a stock option.