Option A correctly uses the SET statement to combine the three datasets vertically, creating a single dataset where each observation represents a customer, order, or product. The code will automatically append the observations from each dataset, creating the desired combined dataset. The other options either include incorrect syntax or fail to combine the datasets vertically as intended.

The correct option is A. The 'WHERE statement in PROC SORT is used to filter the data before sorting. In this case, we want to sort only those records where 'CUSTOMER_ID' is greater than 1000. Option A correctly uses the 'WHERE statement to filter the data and then sorts the filtered data by 'STATE'. The other options either use the 'WHERE statement incorrectly or do not filter the data before sorting, resulting in incorrect sorting.

The correct code uses 'infile 'financial_data.csv' dlm=',' firstobs=l;' to specify the file, delimiter, and start reading from the first observation (header row). 'input variablel $ variable2 $ variable3;' reads the data into variables, assuming the data is character type- 'dsd' would be used for delimited data with variable names in the first row, while "firstobs=2 would skip the header row.

It correctly uses the 'keep' option in the 'data' statement to retain only the CustomerlD and Total_Purchases variables. It also utilizes the 'if statement to filter for customers with at least 5 purchases within the last year. The 'OUtPUt' statement writes the filtered observations to the Loyal_Customers dataset. Options A, B, C, and E are incorrect. Option A and E are incorrect because they attempt to specify the variables to be output directly within the 'output' statement, which is not the correct syntax. Option B is incorrect because it does not specify the variables to be retained in the new dataset. Option C is incorrect because it uses the 'keep' option correctly, but the 'output' statement is missing the dataset name.

The correct answers are A and C. The function calculates the number of intervals between two dates. The 'days' interval is used to calculate the number of days. The 'today()' function returns the current date. Option A correctly calculates both 'CUSTOMER_AGE and but doesn't apply any formatting. Option B uses 'date()' , which returns the date of the last data step execution, not the current date. Option C correctly calculates both and and applies the format to display the values as integers. Option D uses which returns the date of the last data step execution, not the current date, and also applies the '8.' format. Option E uses , which returns the date of the last data step execution, not the current date.