大家好，
有一道在advanced 130里的题不懂，求大神解答。题目是130-v2 的第80题， 如下：

80. The following SAS program is submitted:

%let rc = Begin;

%macro test;

  data out;

  set sashelp.prdsale nobs = totalobs;

  if totalobs > 10 then do;

    %let rc = high;

     end;

  else do;

    %let rc = low;

  end;

  run;

%mend;

%let rc = Before Execution;

%test

The data set SASHELP.PRDSALE has 50 observations. What is the value of the variable RC when the macro finishes execution?

A.low

B.high

C.Begin

D.Before Execution

答案是a，我也跑的程序的确是a。
请大神指教！
感谢！