What description of the standard ratio is not appropriate? 1. The optimal financial ratio is the financial ratio that makes the enterprise value the largest. 2.The past average ratio is mainly used for time series analysis, and it is difficult to use for relative comparison between companies. 3.The ideal benchmark is set by experience. 4. The optimal financial ratio can be the target financial ratio of the entity. 5. The industrial average ratio of the Bank of Korea's corporate management analysis is calculated by a simple average method.