The correct answer is option C. The BY statement in PROC SORT specifies the variables to sort by and their order The keywords ASCENDING and DESCENDING control the sorting direction. In this case, we need to sort by 'REGION' ascending, then 'PRODUCT' descending, and finally 'SALES_AMOUNT' ascending. Option C correctly reflects this order, while other options have incorrect sorting directions or missing keywords.

Both options A and B are correct. They achieve the desired output using different approaches: Option A: It uses the OUT: option to create a temporary dataset called 'TEMP' and then uses the OBS=IO option within a subsequent PROC PRINT statement to display the first 10 observations of 'TEMP. This allows for additional customization or processing of the data before displaying the final report. Option B: It directly limits the number of observations displayed using the OBS=IO option within the same PROC PRINT statement. This is a more concise approach if you only need to display the first 10 observations without further manipulation. Both options use the LABEL option to assign a title, NOOBS to suppress observation numbers, and the FOOTNOTE option to add the date to the report footer. Option C, D, and E are incorrect because they either miss the OBS=IO option for limiting observations or lack the correct FOOTNOTE statement to include the date.

The NODUPKEY option in PROC SORT eliminates duplicate rows based on the variables specified in the BY statement. In this case, it will keep only one row for each unique combination of 'PRODUCT_ID' and 'DATE_MANUFACTURED'. The dataset will be sorted by 'PRODUCT_ID' ascending and then by 'DATE_MANUFACTURED' ascending. Therefore, the output dataset will contain only the distinct records from 'PRODUCTS', sorted accordingly.

The TITLE statement with the ACROSS option will span the title across all the columns of the report Options A, B, C and E will not span the title across all the columns of the report- Option A will display title on the left side of the report Option B will display the title as a default title in the report Option C will center the title in the report and option E will justify the title in the report, but not across the report.

Both the KEEP= and DROP= options can be used to select specific variables in a dataset Option A and B use the KEEP= and DROP= options within the SET statement, respectively to achieve the desired result. Option D also uses the DROP= option but outside the SET statement, which is an equally valid way to select specific variables- Option C is incorrect because the KEEP= option needs to be inside the SET statement when used with the DROP= option. Option E is incorrect as the KEEP= option requires variables to be separated by spaces, not commas, within the SET statement.