Answer: Strong-form efficient

## Explanation **Strong-form efficiency** is the correct answer because: 1. **Market Efficiency Forms**: - **Weak-form efficiency**: Security prices fully reflect all historical price and volume information - **Semi-strong-form efficiency**: Security prices fully reflect all publicly available information - **Strong-form efficiency**: Security prices fully reflect **all information**, including both public and **private information** 2. **Key Distinction**: - Strong-form efficiency is the most stringent form where even private or insider information is already incorporated into security prices - This implies that no investor, including corporate insiders, can earn abnormal returns using any type of information 3. **Real-World Context**: - In practice, strong-form efficiency is considered unrealistic because it would mean insider trading is impossible - Most markets are considered to be semi-strong-form efficient at best **Why other options are incorrect**: - **Option A (Weak-form)**: Only reflects historical market data, not private information - **Option B (Semi-strong-form)**: Reflects all public information but not private information **Answer: C - Strong-form efficient**

Author: LeetQuiz .