What is the value of the macro variable MFRIST when the program finishes execution?

Given the SAS data set ONE:

ONE

DIVISION SALES

A 1234

A 3654

B 5678

The following SAS program is submitted:

Data_null_;

Set one;

By divition;

If first.division then

Do;

%let mfirst=sales;

end;

run;

What is the value of the macro variable MFRIST when the program finishes execution?
A . 1234
B . sales
C . 5678
D . null