Exam A00-211 topic 2 question 25 discussion

After a SAS program is submitted, the following is written to the SAS log:
105 data WORK.JANUARY;
106 set WORK.ALLYEAR(keep=Product Month Quantity Cost);
107 if Month='JAN' then output WORK.JANUARY;
108 Sales=Cost * Quantity;
109 drop=Month Quantity Cost;
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ERROR 22-322: Syntax error, expecting one of the following: !,
!!, , *, **, +, -,
, <=, <>, =, >, >=,
AND, EQ, GE, GT, IN, LE, LT, MAX, MIN, NE, NG, NL,
NOTIN, OR, ^=, |, ||, ~=.
110 run;
What data set option could be attached to WORK.JANUARY to replace the DROP statement that generated the error in the log?