The option in PROC FREQ allows you to control the layout of two-way tables by specifying the variables that will appear as rows and columns. In this case, the code CROSSLIST will display customer age groups as rows and product types as columns in the frequency table.

The variable 'calculated_age' is created in the 'proc sqr step and stored in the new data set 'work.new_table'. To refer to this variable in the sproc print' step, you need to specify the data set name 'work.new_table' as the data source. Option B is the correct syntax. Option A is incorrect because 'calculated_age' is not a variable in the 'work.data_set' data set. Options C and D are incorrect because they use the wrong data set names to refer to 'calculated_age'. Option E is incorrect because you cannot use the syntax within the 'vars statement.

The correct answer is option C. This code snippet uses the WHERE clause to filter for sales amounts greater than $10,000- The SUM statement then calculates the total sales amount by region, and the LABEL option assigns a descriptive label to the 'REGION' variable. The NOOBS option suppresses the observation numbers in the output- Options A, B, D, and E contain errors or missing elements. A filters but doesn't aggregate, B aggregates but doesn't filter, D has an incorrect label placement, and E lacks the NOOBS option- Only option C successfully incorporates all necessary elements for the desired report

Option B is the most efficient and accurate approach- It leverages BY group processing with FIRST. And LAST to identify the specific time period for each customer. It avoids the overhead of creating separate DATA steps or PROC SQL queries, making it more efficient. Option A would be inefficient due to multiple DATA steps and merging. Option C, while possible, might not be as efficient as the DATA step solution. Option D introduces unnecessary complexity with macros. Option E is also a viable approach, but it may not be as efficient as using a single DATA step with BY group processing.

The correct option is C: FOOTNOTE AT PAGE / 'This report is based on data from the Sales database.' l;- The 'AT PAGE option within the FOOTNOTE statement ensures that the footnote appears on each page of the report. Option A would add a footnote at the end of the entire report, not on each page. Options B, D, and E are incorrect syntax for the FOOTNOTE statement within PROC REPORT.