1. When attempting to minimize memory usage, the most efficient way to do group processingwhen using the MEANS procedure is to use:
A. the BY statement.
B. GROUPBY with the NOTSORTED specification.
C. the CLASS statement.
D. multiple WHERE statements.

请问这道题的答案是A还是C呢？
网上给的答案两种都有，有没有人考试遇到过这题能给一个确切的答案呢？

谢谢！