Based on the answer explanation, it seems the correct answer is C not A, isn't it?
7.What happens if you use a GROUP BY clause in a PROC SQL step without a summary function?
a. The step does not execute.
b. The first numeric column is summed by default.
c. The GROUP BY clause is changed to an ORDER BY clause.
d. The step executes but does not group or sort data.
Correct answer: a
The GROUP BY clause is used in queries that include one or more summary functions. If you specify a GROUP BY clause in a query that does not contain a summary function, your clause is changed to an ORDER BY clause.