Which alternative program creates an equivalent BASE_BP data set?

The following SAS program is submitted:

Which alternative program creates an equivalent BASE_BP data set?
A . proc sort data=VS (keep=usubjid vsstresn vstestcd)
out=BASE_BP (drop=vstestcd);
where vstestcd in(‘DIABP’,’SYSBP’);
by usubjid;
run;
B . data BASE_BP;
set VS (keep=usubjid vsstresn);
if vstestcd in(‘DIABP’,’SYSBP’);
run;
C . proc sort data=VS (keep=usubjid vsstresn vstestcd)
out=BASE_BP (drop=vstestcd);
by usubjid;
if vstestcd in(‘DIABP’,’SYSBP’);
run;
D . data BASE_BP (keep=usubjid vsstresn vstestcd);
set VS (drop=vstestcd);
if vstestcd in(‘DIABP’,’SYSBP’);
run;

View Answer

Answer: A