Examine this data in the EMPLOYERS table：Which statement will execute successfully?

In SQL, the GROUP BY clause is used in conjunction with aggregate functions to group the result-set by one or more columns.

A. This statement will execute successfully. MAX() is an aggregate function that can be used to return the highest value of the selected column, and SUM() is an aggregate function used to sum the values. Both are valid in the SELECT statement with a GROUP BY clause grouping the results by dept_id.

B. This statement will not execute successfully when used with GROUP BY because LENGTH(last_name) is not an aggregate function and it doesn't appear in the GROUP BY clause. All selected columns that are not under an aggregate function must be included in the GROUP BY clause.

C. This statement will not execute successfully because STDDEV() is an aggregate function that calculates the standard deviation of a set of numbers, and it can only be used on numeric data types. last_name is not a numeric column.

D. This statement will not execute successfully for the same reason as B: INSTR(last_name, 'A') is not an aggregate function and must appear in the GROUP BY clause if it's in the SELECT clause.