Answer: The stock price follows a geometric Brownian motion (GBM) which is a continuous process.

## Explanation This question is asking for the assumption that is NOT part of the basic Black-Scholes model. However, the provided text only shows Option A, which states: "The stock price follows a geometric Brownian motion (GBM) which is a continuous process." This is actually one of the key assumptions of the Black-Scholes model. The standard Black-Scholes assumptions include: 1. **Stock price follows geometric Brownian motion** (continuous process) 2. **No dividends** during the option's life 3. **Efficient markets** (no arbitrage opportunities) 4. **Constant risk-free interest rate** 5. **Constant volatility** 6. **European-style exercise** (exercise only at expiration) 7. **No transaction costs** 8. **Short selling is allowed** Since Option A is actually a valid assumption of the Black-Scholes model, and the question asks for the exception, but no other options are provided in the text, this question appears to be incomplete. In a complete version of this question, the correct answer would be the option that violates one of these assumptions, such as: - The stock pays dividends - Volatility is stochastic - Interest rates are variable - American-style exercise However, based on the limited information provided, we cannot determine the correct answer as the question is incomplete.

Author: LeetQuiz Editorial Team