What are the key assumptions of the Black-Scholes model for European option pricing? Please list and briefly explain at least three assumptions that are crucial for the model's validity, and discuss why each of these assumptions is important.

你在量化分析中使用Black-Scholes模型进行欧式期权定价时，会基于哪些核心假设？请列举并简要解释至少三个你认为对模型成立至关重要的假设，并谈谈这些假设为何重要。