about %if

shiyiming

Who can tell me why the answer is B rather than D? I think it should be D because we need to use  “Thursday”, doesn't it?

Thanks!!!!
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The following SAS program is submitted:
%macro execute;
[_insert_statement_here_]
proc print data=SASUSER.HOUSES;
run;
%end;
%mend execute;
%execute
Which statement completes the program so that the PROC PRINT step executes on Thursday?
A. if &sysday = Thursday then %do;
B. %if &sysday = Thursday %then %do;
C. %if “&sysday” = Thursday %then %do;
D. %if &sysday = “Thursday” %then %do;