$2.[40$ points, ER model$]$ Consider the given coffee sales data set. coffee$\_$shop$\_$sales$\_2023.$ a$)[10$ points$]$ Which data in the dataset have $($unnecessary$)$ redundancy? Explain your answer. b$)[30$ points$]$ Design an ER model to capture the information stored in the dataset. Please draw the ER model electronically and be sure to show it entity sets, relationships, attributes, multiplicities, keys, etc. Be sure to follow the notation described in class and do not use other notations including Crow$$s foot.