Background to the problemsHK Ocean Park sells its products through the gift shops at Ocean Park Hotel, Ocean Park and the online shop on web. Currently, there are three categories (accessory, bag and toy) of products for sale, and a customer can pay the products by cash, cash vouchers (現金券) or both. Each voucher has a fixed value of HK$50, and one or more cash vouchers can be used in each purchase. However, if the purchase is made on the web, the cash will be paid by credit card because no cash voucher will be accepted.Assume you are the IT specialist of this company, the sales manager of HK Ocean Park has asked you to use Excel to record the sales occurred at different locations and analyze the sales data to improve the business. You are given an Excel file OceanParkSales.xlsx which contains two worksheets (Sales and Catalogue) with some data and you are required to modify and format the worksheet Sales to improve the design.In the worksheet Sales, the user will only input data in the cells highlighted in yellow colour in order to save the time in data entry. To reduce input errors, you are required to design formulae for all cells in the four columns (Category, Price, Total and Cash), so that the correct data (e.g. Price, Total etc.) will be displayed automatically when the necessary input data is entered. Also, in this worksheet, apply the skills you have learned in Excel to check if the input data is valid.