The following SAS program is submitted:

data work.sets;    do until (prod gt 6);        prod + 1;    end;run;

Which one of the following is the value of the variable PROD in the output data set?
A. 5
B. 6
C. 7
D. 8

do until不是执行一遍以后再检查是否满足条件吗？prod=7以后难道不是再+1然后再输出？