Among the following differences between big data analysis and traditional data analysis, the correct statement is ().

Traditional data analysis is "reverse analysis", which analyzes what has happened. In the era of big data, data analysis is "forward analysis" and predictive. Traditional data analysis is mainly aimed at structured data. Big data includes not only traditional structured data mainly based on text materials, but also all semi-structured data and unstructured data such as text, pictures, audio and video in the information age, among which semi-structured and unstructured data are the main ones. Big data analysis is based on massive raw data, and there is no need to set research purposes and methods in advance. Instead, we need to find the relationship between data from a large number of data through data mining technology, establish a model, find the root cause of reality, and even form a theory and new cognition. On this basis, the future is predicted and optimized, so as to realize the continuous improvement and innovation in all fields of social operation. Options a, b, c and d are correct.