请教一下SAS ADVANCED 63 中第六十三题:
Item 63
The following SAS program is submitted:
%macro COLS1;
Name Age;
%mend;
%macro COLS2;
Height Weight;
%mend;
proc print data=SASHELP.CLASS;
[_insert_VAR_statement_here_]
run;
Which VAR statement successfully completes the program to produce a report containing four variables?
A. var %COLS1 %COLS2;
B. var %COLS1-%COLS2;
C. var %COLS1 Weight Height;
D. var Weight Height %COLS1;
为什么答案选D呢?求详细解答,不胜感激。